diff --git a/pms/README.rst b/pms/README.rst
index 532ad03192..694afcbfcd 100644
--- a/pms/README.rst
+++ b/pms/README.rst
@@ -56,11 +56,63 @@ You will find the hotel settings in PMS Management > Configuration > Properties
 
 This module required additional configuration for company, accounting, invoicing and user privileges.
 
+Derived room type prices
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+A room type can take its price from another one, e.g. a Superior room costing
+10 more than the Double one, so that the pricelists only need the prices of
+the latter. Set it in the *Derived Price* section of the room type:
+
+* *Price Derived From*: the room type the price is taken from. It must be
+  available in all the properties of the room type, and it can take its price
+  from a third one in turn (e.g. Family = Superior + 20), up to ten levels.
+* *Price Variation Type* and *Price Variation*: a fixed amount, in the currency
+  of the pricelist, or a percentage of the base price. Negative values lower
+  it, and the price never goes below zero.
+* *Price Rounding*: the multiple the prices derived by a percentage are rounded
+  to, e.g. 1 for whole amounts. Zero rounds them to the currency.
+* *Derive in Pricelists*: the pricelists the price is derived in. Leave it
+  empty to derive it in all of them.
+
+Mind that a derived room type with no rule of its own in a pricelist it does
+not derive in gets its sales price there.
+
 Usage
 =====
 
 To use this module, please, read the complete user guide at `<roomdoo.com>`_.
 
+Working with derived room type prices
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The price of a room type is only derived from its base room type on the days
+a pricelist has no rule of its own for it:
+
+* An item of the derived room type in the pricelist sets its price on its
+  dates: it overrides the derivation there, and the room type follows its base
+  again once the item is removed.
+* Rules on a product category or on all products cover the room type as well,
+  so they win over the derivation. Keep them out of the pricelists the room
+  types derive in.
+* The base room type is priced by the same pricelist, with its own rules or
+  derived in turn. With no rule at all, its sales price is the base.
+* Pricelists based on another one through category or global rules (e.g. a
+  channel rate 10% above the standard one) apply on top of the derived price.
+  When they hold rules for the base room type only, the derived room type has
+  no rule there either: its price is derived from the price of the base room
+  type in that pricelist, which may not be what you want (e.g. a breakfast
+  surcharge per guest of the base room type). Give those pricelists rules for
+  the derived room types too, or use category or global rules there instead.
+* The base price is computed for the date and the property of the stay only,
+  not for the guests: modules pricing by occupancy apply their rules to the
+  derived room type afterwards.
+* Prices already set on reservations do not follow later changes of the base
+  price: use *Update prices* on the reservation to recompute them.
+* Massive changes on pricelists leave the derived room types out of the price
+  changes when no room type is selected, so that they keep following their
+  base, except on the dates they have a price of their own, which is kept.
+  Select them explicitly to give them a price of their own.
+
 Bug Tracker
 ===========
 
diff --git a/pms/i18n/es.po b/pms/i18n/es.po
index 5f74b88848..68e42adb82 100644
--- a/pms/i18n/es.po
+++ b/pms/i18n/es.po
@@ -1241,6 +1241,24 @@ msgstr "Debe especificarse un diario para la entidad adquirente %s."
 msgid "A payment acquirer is required to create a transaction."
 msgstr "Se requiere un adquirente de pagos para crear una transacción."
 
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid "A percentage variation must be greater than -100%."
+msgstr "Una variación porcentual debe ser mayor que -100%."
+
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid ""
+"A room type cannot derive its price from itself, directly or through other "
+"room types."
+msgstr ""
+"Un tipo de habitación no puede derivar su precio de sí mismo, ni "
+"directamente ni a través de otros tipos de habitación."
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_folio_advance_payment_inv__advance_payment_method
 msgid ""
@@ -1439,6 +1457,15 @@ msgstr "Añadir al nombre de la habitación"
 msgid "Add to Folio"
 msgstr "Añadir a la Ficha"
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_value
+msgid ""
+"Added to the price of the base room type, as an amount in the currency of "
+"the pricelist or as a percentage of that price. Negative values lower it"
+msgstr ""
+"Se suma al precio del tipo de habitación base, como importe en la moneda de "
+"la tarifa o como porcentaje de ese precio. Los valores negativos lo reducen"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__additional_product_tag_ids
 msgid "Additional Product Tag"
@@ -3980,6 +4007,21 @@ msgid ""
 "order, etc."
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_pricelist_ids
+msgid "Derive in Pricelists"
+msgstr "Derivar en las tarifas"
+
+#. module: pms
+#: model_terms:ir.ui.view,arch_db:pms.pms_room_type_view_form
+msgid "Derived Price"
+msgstr "Precio derivado"
+
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derived_room_type_ids
+msgid "Derived Room Types"
+msgstr "Tipos de habitación derivados"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_folio_sale_line__name
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__description
@@ -4620,6 +4662,11 @@ msgstr "Nombre"
 msgid "Fiscal Position"
 msgstr "Posición Fiscal"
 
+#. module: pms
+#: model:ir.model.fields.selection,name:pms.selection__pms_room_type__price_derivation_type__amount
+msgid "Fixed amount"
+msgstr "Importe fijo"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_ir_pms_property__value_float
 msgid "Float Field Value"
@@ -6533,6 +6580,11 @@ msgstr ""
 " el precio de la reserva original independientemente\n"
 " de lo marcado en la tarifa"
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_massive_changes_wizard__price_derived_room_type_ids
+msgid "Left Out (Derived Price)"
+msgstr "Excluidos (precio derivado)"
+
 #. module: pms
 #: model:ir.model,name:pms.model_pms_wizard_reservation_lines_split
 msgid "Lines available to split"
@@ -8058,6 +8110,11 @@ msgstr "Detos del Checkin Pendientes"
 msgid "Pending arrival"
 msgstr "Llegada Pendiente"
 
+#. module: pms
+#: model:ir.model.fields.selection,name:pms.selection__pms_room_type__price_derivation_type__percent
+msgid "Percentage"
+msgstr "Porcentaje"
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_reservation__commission_percent
 msgid "Percentage corresponding to commission"
@@ -8191,6 +8248,11 @@ msgstr ""
 msgid "Price"
 msgstr "Precio"
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_base_room_type_id
+msgid "Price Derived From"
+msgstr "Precio derivado de"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_folio_sale_line__price_reduce
 msgid "Price Reduce"
@@ -8206,6 +8268,11 @@ msgstr ""
 msgid "Price Reduce Tax included"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_rounding
+msgid "Price Rounding"
+msgstr "Redondeo del precio"
+
 #. module: pms
 #: model_terms:ir.ui.view,arch_db:pms.portal_my_reservation_detail
 msgid "Price Total"
@@ -8216,6 +8283,16 @@ msgstr "Precio total"
 msgid "Price Unit"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_value
+msgid "Price Variation"
+msgstr "Variación del precio"
+
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_type
+msgid "Price Variation Type"
+msgstr "Tipo de variación del precio"
+
 #. module: pms
 #: model_terms:ir.ui.view,arch_db:pms.pms_property_views_form
 msgid "Price and Availability Plans"
@@ -8397,6 +8474,14 @@ msgstr "Tarifas para un canal de venta"
 msgid "Pricelists of the availability plan "
 msgstr "Tarifa del plan de disponibilidad"
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_pricelist_ids
+msgid ""
+"Pricelists where the price is derived. Leave it empty to derive it in all of "
+"them"
+msgstr ""
+"Tarifas en las que se deriva el precio. Déjelo vacío para derivarlo en todas"
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_board_service_room_type__pricelist_ids
 msgid "Pricelists where this Board Service is available"
@@ -9581,6 +9666,15 @@ msgstr "Tipo de habitación para el que se aplica la regla de disponibilidad"
 msgid "Room type line in Booking Engine"
 msgstr "Línea de tipo de habitación en el Motor de Reservas"
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_base_room_type_id
+msgid ""
+"Room type whose price is the base of this one in the pricelists without a "
+"rule of their own for it"
+msgstr ""
+"Tipo de habitación cuyo precio sirve de base al de este en las tarifas que "
+"no tienen una regla propia para él"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_massive_changes_wizard__board_service_room_type_ids
 msgid "Room type's board services"
@@ -9591,6 +9685,37 @@ msgstr "Board services por tipo de habitación"
 msgid "Room types"
 msgstr "Tipo de habitación"
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_massive_changes_wizard__room_type_ids
+msgid ""
+"Room types to apply the changes to. Leave it empty to apply them to all the "
+"room types of the properties, except for the prices of the room types whose "
+"price is derived from another one"
+msgstr ""
+"Tipos de habitación a los que aplicar los cambios. Déjelo vacío para "
+"aplicarlos a todos los tipos de habitación de los hoteles, salvo los precios "
+"de los tipos de habitación cuyo precio se deriva de otro"
+
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_massive_changes_wizard__price_derived_room_type_ids
+msgid ""
+"Room types whose price is derived from another one in the selected "
+"pricelists. As no room type is selected, the new price is not set on them: "
+"they keep following the room type their price is derived from, except on the "
+"dates they have a price of their own, which is kept. Select them explicitly "
+"to give them a price of their own"
+msgstr ""
+"Tipos de habitación cuyo precio se deriva de otro en las tarifas "
+"seleccionadas. Como no se ha seleccionado ningún tipo de habitación, el "
+"nuevo precio no se les aplica: siguen al tipo de habitación del que derivan "
+"su precio, salvo en las fechas en las que tienen un precio propio, que se "
+"mantiene. Selecciónelos expresamente para darles un precio propio"
+
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derived_room_type_ids
+msgid "Room types whose price is derived from this one"
+msgstr "Tipos de habitación cuyo precio se deriva de este"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_reservation__rooms
 msgid "Room/s"
@@ -9661,6 +9786,15 @@ msgstr "Habitaciones que pertenecen al tipo de habitación."
 msgid "Rooms to create"
 msgstr "Salas para crear"
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_rounding
+msgid ""
+"Round the prices derived by a percentage to a multiple of this value, e.g. 1 "
+"for whole amounts. Zero rounds them to the currency"
+msgstr ""
+"Redondea los precios derivados con un porcentaje a un múltiplo de este "
+"valor, p. ej. 1 para importes enteros. Con cero se redondean a la moneda"
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__route_ids
 msgid "Routes"
@@ -11200,6 +11334,21 @@ msgstr ""
 msgid "The price in a reservation line"
 msgstr "El precio en la linea de reserva"
 
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#: code:addons/pms/models/product_pricelist_item.py:0
+#, python-format
+msgid "The price of %(room_type)s is derived through too many levels."
+msgstr "El precio de %(room_type)s se deriva a través de demasiados niveles."
+
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid "The price rounding can't be negative."
+msgstr "El redondeo del precio no puede ser negativo."
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_folio__amount_untaxed
 msgid "The price without taxes on a folio"
@@ -12477,6 +12626,15 @@ msgstr ""
 "Al configurar este campo, el folio será considerado como no facturado, aún "
 "cuando existan cantidades ordenadas pendientes de facturar."
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_type
+msgid ""
+"Whether the variation is a fixed amount or a percentage of the price of the "
+"base room type"
+msgstr ""
+"Si la variación es un importe fijo o un porcentaje del precio del tipo de "
+"habitación base"
+
 #. module: pms
 #: model:pms.amenity,name:pms.pms_amenity_wi_fi
 msgid "Wi-Fi"
diff --git a/pms/i18n/pms.pot b/pms/i18n/pms.pot
index c17cd7a924..4bd55b553a 100644
--- a/pms/i18n/pms.pot
+++ b/pms/i18n/pms.pot
@@ -926,6 +926,22 @@ msgstr ""
 msgid "A payment acquirer is required to create a transaction."
 msgstr ""
 
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid "A percentage variation must be greater than -100%."
+msgstr ""
+
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid ""
+"A room type cannot derive its price from itself, directly or through other "
+"room types."
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_folio_advance_payment_inv__advance_payment_method
 msgid ""
@@ -1114,6 +1130,13 @@ msgstr ""
 msgid "Add to Folio"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_value
+msgid ""
+"Added to the price of the base room type, as an amount in the currency of "
+"the pricelist or as a percentage of that price. Negative values lower it"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__additional_product_tag_ids
 msgid "Additional Product Tag"
@@ -3625,6 +3648,21 @@ msgid ""
 "order, etc."
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_pricelist_ids
+msgid "Derive in Pricelists"
+msgstr ""
+
+#. module: pms
+#: model_terms:ir.ui.view,arch_db:pms.pms_room_type_view_form
+msgid "Derived Price"
+msgstr ""
+
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derived_room_type_ids
+msgid "Derived Room Types"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_folio_sale_line__name
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__description
@@ -4244,6 +4282,11 @@ msgstr ""
 msgid "Fiscal Position"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields.selection,name:pms.selection__pms_room_type__price_derivation_type__amount
+msgid "Fixed amount"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_ir_pms_property__value_float
 msgid "Float Field Value"
@@ -6077,6 +6120,11 @@ msgid ""
 "        of what is marked in the rate"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_massive_changes_wizard__price_derived_room_type_ids
+msgid "Left Out (Derived Price)"
+msgstr ""
+
 #. module: pms
 #: model:ir.model,name:pms.model_pms_wizard_reservation_lines_split
 msgid "Lines available to split"
@@ -7581,6 +7629,11 @@ msgstr ""
 msgid "Pending arrival"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields.selection,name:pms.selection__pms_room_type__price_derivation_type__percent
+msgid "Percentage"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_reservation__commission_percent
 msgid "Percentage corresponding to commission"
@@ -7711,6 +7764,11 @@ msgstr ""
 msgid "Price"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_base_room_type_id
+msgid "Price Derived From"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_folio_sale_line__price_reduce
 msgid "Price Reduce"
@@ -7726,6 +7784,11 @@ msgstr ""
 msgid "Price Reduce Tax included"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_rounding
+msgid "Price Rounding"
+msgstr ""
+
 #. module: pms
 #: model_terms:ir.ui.view,arch_db:pms.portal_my_reservation_detail
 msgid "Price Total"
@@ -7736,6 +7799,16 @@ msgstr ""
 msgid "Price Unit"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_value
+msgid "Price Variation"
+msgstr ""
+
+#. module: pms
+#: model:ir.model.fields,field_description:pms.field_pms_room_type__price_derivation_type
+msgid "Price Variation Type"
+msgstr ""
+
 #. module: pms
 #: model_terms:ir.ui.view,arch_db:pms.pms_property_views_form
 msgid "Price and Availability Plans"
@@ -7915,6 +7988,13 @@ msgstr ""
 msgid "Pricelists of the availability plan "
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_pricelist_ids
+msgid ""
+"Pricelists where the price is derived. Leave it empty to derive it in all of"
+" them"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_board_service_room_type__pricelist_ids
 msgid "Pricelists where this Board Service is available"
@@ -9075,6 +9155,13 @@ msgstr ""
 msgid "Room type line in Booking Engine"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_base_room_type_id
+msgid ""
+"Room type whose price is the base of this one in the pricelists without a "
+"rule of their own for it"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_massive_changes_wizard__board_service_room_type_ids
 msgid "Room type's board services"
@@ -9085,6 +9172,29 @@ msgstr ""
 msgid "Room types"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_massive_changes_wizard__room_type_ids
+msgid ""
+"Room types to apply the changes to. Leave it empty to apply them to all the "
+"room types of the properties, except for the prices of the room types whose "
+"price is derived from another one"
+msgstr ""
+
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_massive_changes_wizard__price_derived_room_type_ids
+msgid ""
+"Room types whose price is derived from another one in the selected "
+"pricelists. As no room type is selected, the new price is not set on them: "
+"they keep following the room type their price is derived from, except on the"
+" dates they have a price of their own, which is kept. Select them explicitly"
+" to give them a price of their own"
+msgstr ""
+
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derived_room_type_ids
+msgid "Room types whose price is derived from this one"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_reservation__rooms
 msgid "Room/s"
@@ -9155,6 +9265,13 @@ msgstr ""
 msgid "Rooms to create"
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_rounding
+msgid ""
+"Round the prices derived by a percentage to a multiple of this value, e.g. 1"
+" for whole amounts. Zero rounds them to the currency"
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,field_description:pms.field_pms_room_type__route_ids
 msgid "Routes"
@@ -10635,6 +10752,21 @@ msgstr ""
 msgid "The price in a reservation line"
 msgstr ""
 
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#: code:addons/pms/models/product_pricelist_item.py:0
+#, python-format
+msgid "The price of %(room_type)s is derived through too many levels."
+msgstr ""
+
+#. module: pms
+#. odoo-python
+#: code:addons/pms/models/pms_room_type.py:0
+#, python-format
+msgid "The price rounding can't be negative."
+msgstr ""
+
 #. module: pms
 #: model:ir.model.fields,help:pms.field_pms_folio__amount_untaxed
 msgid "The price without taxes on a folio"
@@ -11826,6 +11958,13 @@ msgid ""
 "even when there may be ordered quantities pending to invoice."
 msgstr ""
 
+#. module: pms
+#: model:ir.model.fields,help:pms.field_pms_room_type__price_derivation_type
+msgid ""
+"Whether the variation is a fixed amount or a percentage of the price of the "
+"base room type"
+msgstr ""
+
 #. module: pms
 #: model:pms.amenity,name:pms.pms_amenity_wi_fi
 msgid "Wi-Fi"
diff --git a/pms/models/pms_reservation_line.py b/pms/models/pms_reservation_line.py
index faa7b44a02..10ce9becce 100644
--- a/pms/models/pms_reservation_line.py
+++ b/pms/models/pms_reservation_line.py
@@ -241,6 +241,8 @@ def _get_pricelist_price(self):
             currency=currency,
             consumption_date=consumption_date,
             pms_property_id=self.pms_property_id.id,
+            # With no rule, a room type deriving its price needs the pricelist
+            pricelist=self.reservation_id.pricelist_id,
         )
 
         return price
diff --git a/pms/models/pms_room_type.py b/pms/models/pms_room_type.py
index fba64f3cb1..7426668280 100644
--- a/pms/models/pms_room_type.py
+++ b/pms/models/pms_room_type.py
@@ -5,6 +5,7 @@
 
 from odoo import _, api, fields, models
 from odoo.exceptions import ValidationError
+from odoo.tools import float_round
 
 
 class PmsRoomType(models.Model):
@@ -18,6 +19,9 @@ class PmsRoomType(models.Model):
     _inherits = {"product.product": "product_id"}
     _order = "sequence,default_code,name"
     _check_pms_properties_auto = True
+    # Room types a price can be derived through, from the priced one up to the
+    # root of its chain
+    _price_derivation_max_depth = 10
 
     sequence = fields.Integer(
         help="Field used to change the position of the room types in tree view.",
@@ -94,6 +98,53 @@ class PmsRoomType(models.Model):
         help="Minimum price for a room type",
         default=5.0,
     )
+    price_base_room_type_id = fields.Many2one(
+        string="Price Derived From",
+        help="Room type whose price is the base of this one in the pricelists "
+        "without a rule of their own for it",
+        comodel_name="pms.room.type",
+        ondelete="restrict",
+        index=True,
+        check_pms_properties=True,
+    )
+    price_derived_room_type_ids = fields.One2many(
+        string="Derived Room Types",
+        help="Room types whose price is derived from this one",
+        comodel_name="pms.room.type",
+        inverse_name="price_base_room_type_id",
+        check_pms_properties=True,
+    )
+    price_derivation_type = fields.Selection(
+        string="Price Variation Type",
+        help="Whether the variation is a fixed amount or a percentage of the "
+        "price of the base room type",
+        selection=[("amount", "Fixed amount"), ("percent", "Percentage")],
+        default="amount",
+        required=True,
+    )
+    price_derivation_value = fields.Float(
+        string="Price Variation",
+        help="Added to the price of the base room type, as an amount in the "
+        "currency of the pricelist or as a percentage of that price. Negative "
+        "values lower it",
+        digits="Product Price",
+    )
+    price_derivation_rounding = fields.Float(
+        string="Price Rounding",
+        help="Round the prices derived by a percentage to a multiple of this "
+        "value, e.g. 1 for whole amounts. Zero rounds them to the currency",
+        digits="Product Price",
+    )
+    price_derivation_pricelist_ids = fields.Many2many(
+        string="Derive in Pricelists",
+        help="Pricelists where the price is derived. Leave it empty to derive "
+        "it in all of them",
+        comodel_name="product.pricelist",
+        relation="pms_room_type_price_derivation_pricelist_rel",
+        column1="room_type_id",
+        column2="pricelist_id",
+        check_pms_properties=True,
+    )
 
     def name_get(self):
         result = []
@@ -186,6 +237,51 @@ def _check_code_property_company_uniqueness(self):
                     if other and other != rec:
                         raise ValidationError(msg)
 
+    @api.constrains("price_base_room_type_id")
+    def _check_price_base_room_type_id(self):
+        """A price cannot be derived in a loop, nor through endless chains.
+
+        Prices are derived on the fly, level by level, so a loop would never
+        end and the engine refuses to follow chains longer than
+        ``_price_derivation_max_depth``: refuse both when they are set up
+        rather than when selling.
+        """
+        if not self._check_recursion(parent="price_base_room_type_id"):
+            raise ValidationError(
+                _(
+                    "A room type cannot derive its price from itself, directly "
+                    "or through other room types."
+                )
+            )
+        # All of them, also the archived ones and the ones out of the access
+        # of the current user
+        room_types = self.sudo().with_context(active_test=False)
+        for room_type in room_types | room_types._get_price_derivation_descendants():
+            depth = room_type._get_price_derivation_depth()
+            if depth > self._price_derivation_max_depth:
+                raise ValidationError(
+                    _(
+                        "The price of %(room_type)s is derived through too many "
+                        "levels.",
+                        room_type=room_type.display_name,
+                    )
+                )
+
+    @api.constrains(
+        "price_derivation_type", "price_derivation_value", "price_derivation_rounding"
+    )
+    def _check_price_derivation_values(self):
+        for room_type in self:
+            if (
+                room_type.price_derivation_type == "percent"
+                and room_type.price_derivation_value <= -100
+            ):
+                raise ValidationError(
+                    _("A percentage variation must be greater than -100%.")
+                )
+            if room_type.price_derivation_rounding < 0:
+                raise ValidationError(_("The price rounding can't be negative."))
+
     # ORM Overrides
     # TODO: Review Check product fields default values to room
     @api.model_create_multi
@@ -235,3 +331,78 @@ def get_default_board_service(self, pms_property_id, room_type_id, pricelist_id)
             or False
         )
         return board_service_default
+
+    def _get_price_derivation(self, pricelist):
+        """The room types of self whose price is derived in the pricelist.
+
+        A room type derives its price from its base room type in the
+        pricelists it is set to derive in, or in all of them when none is set.
+        This is only where the derivation applies: the engine still uses a
+        rule of the pricelist covering the room type whenever there is one.
+        Callers only rely on the result being empty or not, so the variation
+        can come from elsewhere (e.g. a rule per pricelist) in the future.
+        It is the same whoever asks: the configuration is read as stored.
+        """
+        if not pricelist:
+            return self.browse()
+        # Read as stored: neither the access of the current user to the
+        # pricelists nor archiving them may empty a restriction, which would
+        # make the room type derive in all the pricelists
+        stored = self.sudo().with_context(active_test=False)
+        return self & stored.filtered(
+            lambda room_type: room_type.price_base_room_type_id
+            and (
+                not room_type.price_derivation_pricelist_ids
+                or pricelist.id in room_type.price_derivation_pricelist_ids.ids
+            )
+        )
+
+    def _derive_price(self, base_price, currency=None):
+        """Apply the price variation of the room type to the price of its base.
+
+        The variation is an amount, in the currency of the pricelist, or a
+        percentage of the base price. Prices derived by a percentage are
+        rounded to the multiple set on the room type, if any, and the result
+        to the currency. It never goes below zero.
+        """
+        self.ensure_one()
+        if self.price_derivation_type == "percent":
+            price = base_price * (1 + self.price_derivation_value / 100)
+            if self.price_derivation_rounding:
+                price = float_round(
+                    price, precision_rounding=self.price_derivation_rounding
+                )
+        else:
+            price = base_price + self.price_derivation_value
+        if currency:
+            price = currency.round(price)
+        return max(price, 0.0)
+
+    def _get_price_derivation_descendants(self):
+        """The room types deriving their price from self, at any level.
+
+        Breadth first, so every room type comes after the one its price is
+        derived from. The room types of self are not part of the result.
+        """
+        descendants = self.browse()
+        derived = self.price_derived_room_type_ids
+        while derived:
+            # Guard against loops written bypassing the constraints
+            derived -= self | descendants
+            descendants |= derived
+            derived = derived.price_derived_room_type_ids
+        return descendants
+
+    def _get_price_derivation_depth(self):
+        """How many room types the price goes through up to the root one.
+
+        Counting stops past ``_price_derivation_max_depth``, which is all
+        callers need to know and keeps it finite on loops.
+        """
+        self.ensure_one()
+        depth = 0
+        base_room_type = self.price_base_room_type_id
+        while base_room_type and depth <= self._price_derivation_max_depth:
+            depth += 1
+            base_room_type = base_room_type.price_base_room_type_id
+        return depth
diff --git a/pms/models/product_pricelist_item.py b/pms/models/product_pricelist_item.py
index d3b02c2266..8077386e1e 100644
--- a/pms/models/product_pricelist_item.py
+++ b/pms/models/product_pricelist_item.py
@@ -1,6 +1,7 @@
 # Copyright 2017  Alexandre Díaz, Pablo Quesada, Darío Lodeiros
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
-from odoo import api, fields, models, tools
+from odoo import _, api, fields, models, tools
+from odoo.exceptions import UserError
 
 
 class ProductPricelistItem(models.Model):
@@ -233,9 +234,19 @@ def _compute_base_consumption_price(
 
         :returns: base price, expressed in provided pricelist currency
         :rtype: float
+
+        With no rule (empty self), a room type deriving its price from another
+        one gets it from the price of that room type instead of its list price.
         """
         target_currency.ensure_one()
 
+        if not self:
+            price = self._compute_derived_room_type_price(
+                product, quantity, uom, date, target_currency, **kwargs
+            )
+            if price is not None:
+                return price
+
         rule_base = self.base or "list_price"
         if rule_base == "pricelist" and self.base_pricelist_id:
             price = self.base_pricelist_id._get_product_price(
@@ -254,3 +265,84 @@ def _compute_base_consumption_price(
                 price, target_currency, self.env.company, date, round=False
             )
         return price
+
+    def _compute_derived_room_type_price(
+        self, product, quantity, uom, date, target_currency, **kwargs
+    ):
+        """Price of a room type derived from the price of its base room type.
+
+        Only reached when the pricelist has no rule at all for the product:
+        any rule covering the room type, its own items (overrides) as well as
+        generic rules, wins over the derivation. The base room type is priced
+        by the same pricelist, so it can derive its price in turn.
+
+        :returns: the derived price, in the target currency, or None when the
+            product is not a room type deriving its price in the pricelist of
+            the computation (``kwargs["pricelist"]``)
+        """
+        pricelist = kwargs.get("pricelist")
+        if (
+            not pricelist
+            or not kwargs.get("consumption_date")
+            or not kwargs.get("pms_property_id")
+            or product._name != "product.product"
+        ):
+            return None
+        # Cheap lookup restricted to room types with a base one, as most
+        # products priced with no rule are not room types deriving their price.
+        # As superuser: the derivation is configuration, the price must not
+        # depend on what the user pricing can access
+        room_type = (
+            self.env["pms.room.type"]
+            .sudo()
+            .with_context(active_test=False)
+            .search(
+                [
+                    ("product_id", "=", product.id),
+                    ("price_base_room_type_id", "!=", False),
+                ],
+                limit=1,
+            )
+        )
+        if not room_type._get_price_derivation(pricelist):
+            return None
+        depth = kwargs.get("price_derivation_depth", 0)
+        if depth >= room_type._price_derivation_max_depth:
+            raise UserError(
+                _(
+                    "The price of %(room_type)s is derived through too many levels.",
+                    room_type=room_type.display_name,
+                )
+            )
+        base_product = room_type.price_base_room_type_id.product_id
+        base_price = pricelist._get_product_price(
+            base_product,
+            quantity,
+            uom=base_product.uom_id,
+            date=date,
+            price_derivation_depth=depth + 1,
+            **self._get_price_derivation_base_kwargs(kwargs),
+        )
+        price = room_type._derive_price(base_price, pricelist.currency_id)
+        if base_product.uom_id != uom:
+            price = base_product.uom_id._compute_price(price, uom)
+        if pricelist.currency_id != target_currency:
+            price = pricelist.currency_id._convert(
+                price, target_currency, self.env.company, date, round=False
+            )
+        return price
+
+    @api.model
+    def _get_price_derivation_base_kwargs(self, kwargs):
+        """What the price of a base room type is computed with.
+
+        The dimensions of the stay only: the base room type is priced for its
+        default occupancy, and whatever depends on the guests (occupancy,
+        children...) is applied afterwards to the derived room type, by the
+        computation of its own price. Extend it to forward other dimensions.
+        """
+        return {
+            key: kwargs[key]
+            for key in ("consumption_date", "pms_property_id")
+            if key in kwargs
+        }
diff --git a/pms/readme/CONFIGURE.rst b/pms/readme/CONFIGURE.rst
index 940574e837..3c2fae83c6 100644
--- a/pms/readme/CONFIGURE.rst
+++ b/pms/readme/CONFIGURE.rst
@@ -1,3 +1,24 @@
 You will find the hotel settings in PMS Management > Configuration > Properties > Your Property.
 
 This module required additional configuration for company, accounting, invoicing and user privileges.
+
+Derived room type prices
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+A room type can take its price from another one, e.g. a Superior room costing
+10 more than the Double one, so that the pricelists only need the prices of
+the latter. Set it in the *Derived Price* section of the room type:
+
+* *Price Derived From*: the room type the price is taken from. It must be
+  available in all the properties of the room type, and it can take its price
+  from a third one in turn (e.g. Family = Superior + 20), up to ten levels.
+* *Price Variation Type* and *Price Variation*: a fixed amount, in the currency
+  of the pricelist, or a percentage of the base price. Negative values lower
+  it, and the price never goes below zero.
+* *Price Rounding*: the multiple the prices derived by a percentage are rounded
+  to, e.g. 1 for whole amounts. Zero rounds them to the currency.
+* *Derive in Pricelists*: the pricelists the price is derived in. Leave it
+  empty to derive it in all of them.
+
+Mind that a derived room type with no rule of its own in a pricelist it does
+not derive in gets its sales price there.
diff --git a/pms/readme/USAGE.rst b/pms/readme/USAGE.rst
index e6a897c6ad..b2391d39a2 100644
--- a/pms/readme/USAGE.rst
+++ b/pms/readme/USAGE.rst
@@ -1 +1,32 @@
 To use this module, please, read the complete user guide at `<roomdoo.com>`_.
+
+Working with derived room type prices
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The price of a room type is only derived from its base room type on the days
+a pricelist has no rule of its own for it:
+
+* An item of the derived room type in the pricelist sets its price on its
+  dates: it overrides the derivation there, and the room type follows its base
+  again once the item is removed.
+* Rules on a product category or on all products cover the room type as well,
+  so they win over the derivation. Keep them out of the pricelists the room
+  types derive in.
+* The base room type is priced by the same pricelist, with its own rules or
+  derived in turn. With no rule at all, its sales price is the base.
+* Pricelists based on another one through category or global rules (e.g. a
+  channel rate 10% above the standard one) apply on top of the derived price.
+  When they hold rules for the base room type only, the derived room type has
+  no rule there either: its price is derived from the price of the base room
+  type in that pricelist, which may not be what you want (e.g. a breakfast
+  surcharge per guest of the base room type). Give those pricelists rules for
+  the derived room types too, or use category or global rules there instead.
+* The base price is computed for the date and the property of the stay only,
+  not for the guests: modules pricing by occupancy apply their rules to the
+  derived room type afterwards.
+* Prices already set on reservations do not follow later changes of the base
+  price: use *Update prices* on the reservation to recompute them.
+* Massive changes on pricelists leave the derived room types out of the price
+  changes when no room type is selected, so that they keep following their
+  base, except on the dates they have a price of their own, which is kept.
+  Select them explicitly to give them a price of their own.
diff --git a/pms/static/description/index.html b/pms/static/description/index.html
index f113520b35..78d36520e1 100644
--- a/pms/static/description/index.html
+++ b/pms/static/description/index.html
@@ -3,7 +3,7 @@
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <meta name="generator" content="Docutils: https://docutils.sourceforge.io/" />
-<title>PMS (Property Management System)</title>
+<title>README.rst</title>
 <style type="text/css">
 
 /*
@@ -383,13 +383,19 @@ <h1>PMS (Property Management System)</h1>
 <div class="contents local topic" id="contents">
 <ul class="simple">
 <li><a class="reference internal" href="#installation" id="toc-entry-1">Installation</a></li>
-<li><a class="reference internal" href="#configuration" id="toc-entry-2">Configuration</a></li>
-<li><a class="reference internal" href="#usage" id="toc-entry-3">Usage</a></li>
-<li><a class="reference internal" href="#bug-tracker" id="toc-entry-4">Bug Tracker</a></li>
-<li><a class="reference internal" href="#credits" id="toc-entry-5">Credits</a><ul>
-<li><a class="reference internal" href="#authors" id="toc-entry-6">Authors</a></li>
-<li><a class="reference internal" href="#contributors" id="toc-entry-7">Contributors</a></li>
-<li><a class="reference internal" href="#maintainers" id="toc-entry-8">Maintainers</a></li>
+<li><a class="reference internal" href="#configuration" id="toc-entry-2">Configuration</a><ul>
+<li><a class="reference internal" href="#derived-room-type-prices" id="toc-entry-3">Derived room type prices</a></li>
+</ul>
+</li>
+<li><a class="reference internal" href="#usage" id="toc-entry-4">Usage</a><ul>
+<li><a class="reference internal" href="#working-with-derived-room-type-prices" id="toc-entry-5">Working with derived room type prices</a></li>
+</ul>
+</li>
+<li><a class="reference internal" href="#bug-tracker" id="toc-entry-6">Bug Tracker</a></li>
+<li><a class="reference internal" href="#credits" id="toc-entry-7">Credits</a><ul>
+<li><a class="reference internal" href="#authors" id="toc-entry-8">Authors</a></li>
+<li><a class="reference internal" href="#contributors" id="toc-entry-9">Contributors</a></li>
+<li><a class="reference internal" href="#maintainers" id="toc-entry-10">Maintainers</a></li>
 </ul>
 </li>
 </ul>
@@ -403,13 +409,64 @@ <h2><a class="toc-backref" href="#toc-entry-1">Installation</a></h2>
 <h2><a class="toc-backref" href="#toc-entry-2">Configuration</a></h2>
 <p>You will find the hotel settings in PMS Management &gt; Configuration &gt; Properties &gt; Your Property.</p>
 <p>This module required additional configuration for company, accounting, invoicing and user privileges.</p>
+<div class="section" id="derived-room-type-prices">
+<h3><a class="toc-backref" href="#toc-entry-3">Derived room type prices</a></h3>
+<p>A room type can take its price from another one, e.g. a Superior room costing
+10 more than the Double one, so that the pricelists only need the prices of
+the latter. Set it in the <em>Derived Price</em> section of the room type:</p>
+<ul class="simple">
+<li><em>Price Derived From</em>: the room type the price is taken from. It must be
+available in all the properties of the room type, and it can take its price
+from a third one in turn (e.g. Family = Superior + 20), up to ten levels.</li>
+<li><em>Price Variation Type</em> and <em>Price Variation</em>: a fixed amount, in the currency
+of the pricelist, or a percentage of the base price. Negative values lower
+it, and the price never goes below zero.</li>
+<li><em>Price Rounding</em>: the multiple the prices derived by a percentage are rounded
+to, e.g. 1 for whole amounts. Zero rounds them to the currency.</li>
+<li><em>Derive in Pricelists</em>: the pricelists the price is derived in. Leave it
+empty to derive it in all of them.</li>
+</ul>
+<p>Mind that a derived room type with no rule of its own in a pricelist it does
+not derive in gets its sales price there.</p>
+</div>
 </div>
 <div class="section" id="usage">
-<h2><a class="toc-backref" href="#toc-entry-3">Usage</a></h2>
+<h2><a class="toc-backref" href="#toc-entry-4">Usage</a></h2>
 <p>To use this module, please, read the complete user guide at <a class="reference external" href="roomdoo.com">roomdoo.com</a>.</p>
+<div class="section" id="working-with-derived-room-type-prices">
+<h3><a class="toc-backref" href="#toc-entry-5">Working with derived room type prices</a></h3>
+<p>The price of a room type is only derived from its base room type on the days
+a pricelist has no rule of its own for it:</p>
+<ul class="simple">
+<li>An item of the derived room type in the pricelist sets its price on its
+dates: it overrides the derivation there, and the room type follows its base
+again once the item is removed.</li>
+<li>Rules on a product category or on all products cover the room type as well,
+so they win over the derivation. Keep them out of the pricelists the room
+types derive in.</li>
+<li>The base room type is priced by the same pricelist, with its own rules or
+derived in turn. With no rule at all, its sales price is the base.</li>
+<li>Pricelists based on another one through category or global rules (e.g. a
+channel rate 10% above the standard one) apply on top of the derived price.
+When they hold rules for the base room type only, the derived room type has
+no rule there either: its price is derived from the price of the base room
+type in that pricelist, which may not be what you want (e.g. a breakfast
+surcharge per guest of the base room type). Give those pricelists rules for
+the derived room types too, or use category or global rules there instead.</li>
+<li>The base price is computed for the date and the property of the stay only,
+not for the guests: modules pricing by occupancy apply their rules to the
+derived room type afterwards.</li>
+<li>Prices already set on reservations do not follow later changes of the base
+price: use <em>Update prices</em> on the reservation to recompute them.</li>
+<li>Massive changes on pricelists leave the derived room types out of the price
+changes when no room type is selected, so that they keep following their
+base, except on the dates they have a price of their own, which is kept.
+Select them explicitly to give them a price of their own.</li>
+</ul>
+</div>
 </div>
 <div class="section" id="bug-tracker">
-<h2><a class="toc-backref" href="#toc-entry-4">Bug Tracker</a></h2>
+<h2><a class="toc-backref" href="#toc-entry-6">Bug Tracker</a></h2>
 <p>Bugs are tracked on <a class="reference external" href="https://github.com/OCA/pms/issues">GitHub Issues</a>.
 In case of trouble, please check there if your issue has already been reported.
 If you spotted it first, help us to smash it by providing a detailed and welcomed
@@ -417,15 +474,15 @@ <h2><a class="toc-backref" href="#toc-entry-4">Bug Tracker</a></h2>
 <p>Do not contact contributors directly about support or help with technical issues.</p>
 </div>
 <div class="section" id="credits">
-<h2><a class="toc-backref" href="#toc-entry-5">Credits</a></h2>
+<h2><a class="toc-backref" href="#toc-entry-7">Credits</a></h2>
 <div class="section" id="authors">
-<h3><a class="toc-backref" href="#toc-entry-6">Authors</a></h3>
+<h3><a class="toc-backref" href="#toc-entry-8">Authors</a></h3>
 <ul class="simple">
 <li>Commit [Sun]</li>
 </ul>
 </div>
 <div class="section" id="contributors">
-<h3><a class="toc-backref" href="#toc-entry-7">Contributors</a></h3>
+<h3><a class="toc-backref" href="#toc-entry-9">Contributors</a></h3>
 <ul class="simple">
 <li>Alexandre Díaz</li>
 <li>Pablo Quesada</li>
@@ -442,7 +499,7 @@ <h3><a class="toc-backref" href="#toc-entry-7">Contributors</a></h3>
 </ul>
 </div>
 <div class="section" id="maintainers">
-<h3><a class="toc-backref" href="#toc-entry-8">Maintainers</a></h3>
+<h3><a class="toc-backref" href="#toc-entry-10">Maintainers</a></h3>
 <p>This module is maintained by the OCA.</p>
 <a class="reference external image-reference" href="https://odoo-community.org">
 <img alt="Odoo Community Association" src="https://odoo-community.org/logo.png" />
diff --git a/pms/tests/__init__.py b/pms/tests/__init__.py
index 35cf87cc43..6e5e474e14 100644
--- a/pms/tests/__init__.py
+++ b/pms/tests/__init__.py
@@ -26,6 +26,7 @@
 from . import test_pms_folio
 from . import test_pms_availability_plan_rules
 from . import test_pms_room_type
+from . import test_pms_room_type_price_derivation
 from . import test_pms_room_type_class
 from . import test_pms_board_service
 from . import test_pms_wizard_massive_changes
diff --git a/pms/tests/test_pms_room_type_price_derivation.py b/pms/tests/test_pms_room_type_price_derivation.py
new file mode 100644
index 0000000000..27e08f4458
--- /dev/null
+++ b/pms/tests/test_pms_room_type_price_derivation.py
@@ -0,0 +1,797 @@
+# Copyright 2026 Commit [Sun]
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+import datetime
+from contextlib import contextmanager
+from unittest.mock import patch
+
+from odoo import fields
+from odoo.exceptions import UserError, ValidationError
+
+from .common import TestPms
+
+
+class TestPmsRoomTypePriceDerivation(TestPms):
+    """Room types taking their price from another one (their base room type).
+
+    The Double room type is priced in the pricelist and the Superior one is
+    set to cost 10 more, with no items of its own.
+    """
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.date = fields.Date.today() + datetime.timedelta(days=30)
+        cls.next_date = cls.date + datetime.timedelta(days=1)
+        cls.pms_property2 = cls.env["pms.property"].create(
+            {
+                "name": "Property 2",
+                "company_id": cls.company1.id,
+                "default_pricelist_id": cls.pricelist1.id,
+            }
+        )
+        cls.pricelist2 = cls.env["product.pricelist"].create(
+            {
+                "name": "Pricelist 2",
+                "availability_plan_id": cls.availability_plan1.id,
+                "is_pms_available": True,
+            }
+        )
+        cls.double = cls._create_room_type("Double", "PD_DBL", list_price=400.0)
+        cls.superior = cls._create_room_type(
+            "Superior",
+            "PD_SUP",
+            list_price=300.0,
+            price_base_room_type_id=cls.double.id,
+            price_derivation_value=10.0,
+        )
+        cls.double_item = cls._set_price(cls.double, cls.date, 100.0)
+        cls._set_price(cls.double, cls.next_date, 120.0)
+
+    @classmethod
+    def _create_room_type(cls, name, code, **vals):
+        values = {
+            "name": name,
+            "default_code": code,
+            "class_id": cls.room_type_class1.id,
+            "pms_property_ids": [(6, 0, [cls.pms_property1.id])],
+        }
+        values.update(vals)
+        return cls.env["pms.room.type"].create(values)
+
+    @classmethod
+    def _set_price(cls, room_type, date, price, pricelist=None, pms_property=None):
+        return cls.env["product.pricelist.item"].create(
+            {
+                "pricelist_id": (pricelist or cls.pricelist1).id,
+                "applied_on": "0_product_variant",
+                "product_id": room_type.product_id.id,
+                "compute_price": "fixed",
+                "fixed_price": price,
+                "date_start_consumption": date,
+                "date_end_consumption": date,
+                "pms_property_ids": [(6, 0, (pms_property or cls.pms_property1).ids)],
+            }
+        )
+
+    @contextmanager
+    def _assert_refused(self, exception, message):
+        """assertRaisesRegex rolling back what the refused operation wrote."""
+        with self.assertRaises(exception) as refusal:
+            yield
+        self.assertIn(message, str(refusal.exception))
+
+    def _price(self, room_type, date=None, pricelist=None, pms_property=None, **kw):
+        return (pricelist or self.pricelist1)._get_product_price(
+            product=room_type.product_id,
+            quantity=1,
+            consumption_date=date or self.date,
+            pms_property_id=(pms_property or self.pms_property1).id,
+            **kw,
+        )
+
+    # Price computation
+
+    def test_amount_variation(self):
+        """The variation is added to the price of the base room type."""
+        self.assertAlmostEqual(self._price(self.superior), 110.0, places=2)
+        self.assertAlmostEqual(
+            self._price(self.superior, self.next_date), 130.0, places=2
+        )
+        self.superior.price_derivation_value = -15.0
+        self.assertAlmostEqual(
+            self._price(self.superior),
+            85.0,
+            places=2,
+            msg="A change of the variation applies right away",
+        )
+
+    def test_percent_variation_rounded_to_currency(self):
+        """With no rounding set, a percentage is rounded to the currency."""
+        self._set_price(self.double, self.date + datetime.timedelta(days=2), 65.57)
+        self.superior.write(
+            {"price_derivation_type": "percent", "price_derivation_value": 10.0}
+        )
+        self.assertAlmostEqual(self._price(self.superior), 110.0, places=2)
+        self.assertAlmostEqual(
+            self._price(self.superior, self.date + datetime.timedelta(days=2)),
+            72.13,
+            places=2,
+            msg="65.57 + 10% = 72.127 rounds to the cent",
+        )
+
+    def test_percent_variation_rounded_to_multiple(self):
+        """A percentage is rounded to the multiple set on the room type."""
+        self._set_price(self.double, self.date + datetime.timedelta(days=2), 65.0)
+        self.superior.write(
+            {
+                "price_derivation_type": "percent",
+                "price_derivation_value": 10.0,
+                "price_derivation_rounding": 1.0,
+            }
+        )
+        self.assertAlmostEqual(
+            self._price(self.superior, self.date + datetime.timedelta(days=2)),
+            72.0,
+            places=2,
+            msg="65 + 10% = 71.5 rounds to 72",
+        )
+        self.superior.price_derivation_rounding = 5.0
+        self.assertAlmostEqual(
+            self._price(self.superior, self.date + datetime.timedelta(days=2)),
+            70.0,
+            places=2,
+        )
+
+    def test_own_item_overrides_its_date_only(self):
+        """An item of the derived room type sets its price on its date."""
+        self._set_price(self.superior, self.date, 150.0)
+        self.assertAlmostEqual(self._price(self.superior), 150.0, places=2)
+        self.assertAlmostEqual(
+            self._price(self.superior, self.next_date),
+            130.0,
+            places=2,
+            msg="The other dates keep following the base room type",
+        )
+
+    def test_chain_of_derivations(self):
+        """A base room type can derive its price from a third one."""
+        family = self._create_room_type(
+            "Family",
+            "PD_FAM",
+            price_base_room_type_id=self.superior.id,
+            price_derivation_type="percent",
+            price_derivation_value=5.0,
+        )
+        self.assertAlmostEqual(
+            self._price(family), 115.5, places=2, msg="(100 + 10) + 5%"
+        )
+        self.assertEqual(
+            self.double._get_price_derivation_descendants(),
+            self.superior | family,
+        )
+        self.assertEqual(
+            self.double._get_price_derivation_descendants()[0],
+            self.superior,
+            "Each room type comes after the one its price derives from",
+        )
+
+    def test_base_without_rule_uses_its_list_price(self):
+        """With no rule for the base room type, its list price is the base."""
+        date = self.date + datetime.timedelta(days=5)
+        self.assertAlmostEqual(self._price(self.double, date), 400.0, places=2)
+        self.assertAlmostEqual(self._price(self.superior, date), 410.0, places=2)
+
+    def test_price_never_goes_negative(self):
+        """A negative variation larger than the base price floors at zero."""
+        self.superior.price_derivation_value = -150.0
+        self.assertEqual(self._price(self.superior), 0.0)
+
+    def test_price_per_property(self):
+        """The base price is the one of the property being priced."""
+        properties = self.pms_property1 | self.pms_property2
+        twin = self._create_room_type(
+            "Twin", "PD_TWN", pms_property_ids=[(6, 0, properties.ids)]
+        )
+        twin_superior = self._create_room_type(
+            "Twin Superior",
+            "PD_TWS",
+            pms_property_ids=[(6, 0, properties.ids)],
+            price_base_room_type_id=twin.id,
+            price_derivation_value=10.0,
+        )
+        self._set_price(twin, self.date, 100.0)
+        self._set_price(twin, self.date, 200.0, pms_property=self.pms_property2)
+        self.assertAlmostEqual(self._price(twin_superior), 110.0, places=2)
+        self.assertAlmostEqual(
+            self._price(twin_superior, pms_property=self.pms_property2),
+            210.0,
+            places=2,
+        )
+
+    def test_generic_rule_wins_over_derivation(self):
+        """A category or global rule covering the room type is a rule of its own.
+
+        The derivation only applies when the pricelist has no rule at all for
+        the room type, so a generic rule of the pricelist prices it instead.
+        """
+        self.env["product.pricelist.item"].create(
+            {
+                "pricelist_id": self.pricelist1.id,
+                "applied_on": "2_product_category",
+                "categ_id": self.superior.categ_id.id,
+                "compute_price": "percentage",
+                "percent_price": 50.0,
+            }
+        )
+        self.assertAlmostEqual(
+            self._price(self.superior), 150.0, places=2, msg="50% of 300"
+        )
+        self.assertAlmostEqual(
+            self._price(self.double),
+            100.0,
+            places=2,
+            msg="Items of the room type itself still win over the generic rule",
+        )
+
+    def test_pricelist_restriction(self):
+        """The price is only derived in the pricelists set on the room type."""
+        self._set_price(self.double, self.date, 90.0, pricelist=self.pricelist2)
+        self.superior.price_derivation_pricelist_ids = self.pricelist1
+        self.assertAlmostEqual(self._price(self.superior), 110.0, places=2)
+        self.assertAlmostEqual(
+            self._price(self.superior, pricelist=self.pricelist2),
+            300.0,
+            places=2,
+            msg="Out of its pricelists, the room type gets its own list price",
+        )
+        self.assertFalse(self.superior._get_price_derivation(self.pricelist2))
+        self.assertEqual(
+            self.superior._get_price_derivation(self.pricelist1), self.superior
+        )
+        self.assertFalse(self.superior._get_price_derivation(self.pricelist1.browse()))
+
+    def test_pricelist_restriction_to_archived_pricelist(self):
+        """Archiving the pricelists the price is derived in never widens it."""
+        old_rate = self.env["product.pricelist"].create(
+            {"name": "Old Rate", "availability_plan_id": self.availability_plan1.id}
+        )
+        self.superior.price_derivation_pricelist_ids = old_rate
+        old_rate.active = False
+        self.assertFalse(self.superior._get_price_derivation(self.pricelist1))
+        self.assertAlmostEqual(self._price(self.superior), 300.0, places=2)
+
+    def test_derived_pricelist_with_generic_rule_on_top(self):
+        """A pricelist based on another one by a generic rule applies on top.
+
+        E.g. a channel rate being 38% more than the standard one: the derived
+        room type gets 38% more than its derived standard price.
+        """
+        channel_pricelist = self.env["product.pricelist"].create(
+            {
+                "name": "Channel",
+                "item_ids": [
+                    (
+                        0,
+                        0,
+                        {
+                            "applied_on": "2_product_category",
+                            "categ_id": self.superior.categ_id.id,
+                            "compute_price": "formula",
+                            "base": "pricelist",
+                            "base_pricelist_id": self.pricelist1.id,
+                            "price_discount": -38.0,
+                        },
+                    )
+                ],
+            }
+        )
+        self.assertAlmostEqual(
+            self._price(self.double, pricelist=channel_pricelist), 138.0, places=2
+        )
+        self.assertAlmostEqual(
+            self._price(self.superior, pricelist=channel_pricelist),
+            151.8,
+            places=2,
+            msg="(100 + 10) * 1.38",
+        )
+
+    def test_derived_pricelist_with_rules_for_base_only(self):
+        """A pricelist with rules on the base room type only derives from them.
+
+        When a pricelist based on another one holds product rules for the base
+        room type and none for the derived one, the derived room type has no
+        rule there: its price is derived in that pricelist, from the price of
+        the base room type in it (its surcharge included), and not computed by
+        those rules on top of its own base price.
+        """
+        breakfast_pricelist = self.env["product.pricelist"].create(
+            {
+                "name": "Bed and breakfast",
+                "item_ids": [
+                    (
+                        0,
+                        0,
+                        {
+                            "applied_on": "0_product_variant",
+                            "product_id": self.double.product_id.id,
+                            "compute_price": "formula",
+                            "base": "pricelist",
+                            "base_pricelist_id": self.pricelist1.id,
+                            "price_surcharge": 16.0,
+                        },
+                    )
+                ],
+            }
+        )
+        self.superior.write(
+            {"price_derivation_type": "percent", "price_derivation_value": 10.0}
+        )
+        self.assertAlmostEqual(
+            self._price(self.double, pricelist=breakfast_pricelist), 116.0, places=2
+        )
+        self.assertAlmostEqual(
+            self._price(self.superior, pricelist=breakfast_pricelist),
+            127.6,
+            places=2,
+            msg="(100 + 16) + 10%, not (100 + 10%) + 16",
+        )
+        self.superior.price_derivation_pricelist_ids = self.pricelist1
+        self.assertAlmostEqual(
+            self._price(self.superior, pricelist=breakfast_pricelist),
+            300.0,
+            places=2,
+            msg="Not derived there, the room type falls back to its list price",
+        )
+
+    def test_base_price_ignores_guest_details(self):
+        """Only the stay is forwarded to price the base room type.
+
+        Whatever depends on the guests (e.g. the occupancy) is for the derived
+        room type to apply on its own price, never through its base as well.
+        """
+        pricelist_class = type(self.env["product.pricelist"])
+        get_product_price = pricelist_class._get_product_price
+        calls = []
+
+        def spy(pricelist, product, *args, **kwargs):
+            calls.append((product, kwargs))
+            return get_product_price(pricelist, product, *args, **kwargs)
+
+        with patch.object(pricelist_class, "_get_product_price", spy):
+            price = self._price(self.superior, occupancy=3, children=1)
+        self.assertAlmostEqual(price, 110.0, places=2)
+        base_calls = [kw for product, kw in calls if product == self.double.product_id]
+        self.assertEqual(len(base_calls), 1)
+        self.assertEqual(
+            set(base_calls[0]),
+            {
+                "uom",
+                "date",
+                "consumption_date",
+                "pms_property_id",
+                "price_derivation_depth",
+            },
+        )
+
+    def test_no_pricelist_keeps_list_price(self):
+        """Without a pricelist to derive in, the price is the list price."""
+        price = self.env["product.pricelist.item"]._compute_consumption_price(
+            self.superior.product_id,
+            1,
+            self.superior.uom_id,
+            fields.Datetime.now(),
+            currency=self.pricelist1.currency_id,
+            consumption_date=self.date,
+            pms_property_id=self.pms_property1.id,
+        )
+        self.assertAlmostEqual(price, 300.0, places=2)
+
+    def test_other_products_unaffected(self):
+        """Products other than derived room types keep their list price."""
+        product = self.env["product.product"].create(
+            {"name": "Extra Bed", "list_price": 7.0}
+        )
+        self.assertAlmostEqual(
+            self.pricelist1._get_product_price(
+                product,
+                1,
+                consumption_date=self.date,
+                pms_property_id=self.pms_property1.id,
+            ),
+            7.0,
+            places=2,
+        )
+        date = self.date + datetime.timedelta(days=5)
+        self.assertAlmostEqual(self._price(self.double, date), 400.0, places=2)
+
+    # Configuration
+
+    def test_derivation_loop_rejected(self):
+        """A room type cannot derive its price through itself."""
+        with self._assert_refused(ValidationError, "from itself"):
+            self.double.price_base_room_type_id = self.superior
+        with self._assert_refused(ValidationError, "from itself"):
+            self.double.price_base_room_type_id = self.double
+
+    def test_too_many_levels_rejected(self):
+        """Chains are limited to the levels the engine follows."""
+        room_type = self.double
+        for level in range(1, 10):
+            room_type = self._create_room_type(
+                f"Level {level}",
+                f"PD_LVL{level}",
+                price_base_room_type_id=room_type.id,
+                price_derivation_value=1.0,
+            )
+        self.assertEqual(room_type._get_price_derivation_depth(), 9)
+        self.assertAlmostEqual(self._price(room_type), 109.0, places=2)
+        room_type = self._create_room_type(
+            "Level 10",
+            "PD_LVL10",
+            price_base_room_type_id=room_type.id,
+            price_derivation_value=1.0,
+        )
+        self.assertAlmostEqual(self._price(room_type), 110.0, places=2)
+        with self._assert_refused(ValidationError, "too many levels"):
+            self._create_room_type(
+                "Level 11", "PD_LVL11", price_base_room_type_id=room_type.id
+            )
+        with self._assert_refused(ValidationError, "too many levels"):
+            self.double.price_base_room_type_id = self._create_room_type(
+                "Root", "PD_ROOT"
+            )
+
+    def test_runtime_depth_guard(self):
+        """The engine refuses to go deeper than the levels it follows."""
+        with self._assert_refused(UserError, "too many levels"):
+            self._price(self.superior, price_derivation_depth=10)
+
+    def test_percentage_down_to_minus_100_rejected(self):
+        """A percentage cannot take the price down to zero or below."""
+        with self._assert_refused(ValidationError, "greater than -100%"):
+            self.superior.write(
+                {"price_derivation_type": "percent", "price_derivation_value": -100}
+            )
+        self.superior.write(
+            {"price_derivation_type": "percent", "price_derivation_value": -50}
+        )
+        self.assertAlmostEqual(self._price(self.superior), 50.0, places=2)
+        self.superior.price_derivation_type = "amount"
+        self.superior.price_derivation_value = -100
+        self.assertAlmostEqual(
+            self._price(self.superior),
+            0.0,
+            places=2,
+            msg="Amounts are not limited, the price floors at zero",
+        )
+
+    def test_negative_rounding_rejected(self):
+        with self._assert_refused(ValidationError, "rounding"):
+            self.superior.price_derivation_rounding = -1.0
+
+    def test_base_in_other_property_rejected(self):
+        """The base room type must be available in all the properties."""
+        other = self._create_room_type(
+            "Other", "PD_OTH", pms_property_ids=[(6, 0, self.pms_property2.ids)]
+        )
+        with self.assertRaises(UserError):
+            self.superior.price_base_room_type_id = other
+
+    # Flows
+
+    def test_reservation_derived_price_and_update_prices(self):
+        """Reservations get the derived price and keep it until recomputed."""
+        self.env["pms.room"].create(
+            {
+                "pms_property_id": self.pms_property1.id,
+                "name": "Superior 101",
+                "room_type_id": self.superior.id,
+                "capacity": 2,
+            }
+        )
+        reservation = self.env["pms.reservation"].create(
+            {
+                "checkin": self.date,
+                "checkout": self.date + datetime.timedelta(days=2),
+                "room_type_id": self.superior.id,
+                "partner_id": self.env["res.partner"].create({"name": "Guest"}).id,
+                "pms_property_id": self.pms_property1.id,
+                "pricelist_id": self.pricelist1.id,
+                "sale_channel_origin_id": self.env["pms.sale.channel"]
+                .create({"name": "Door", "channel_type": "direct"})
+                .id,
+            }
+        )
+        lines = reservation.reservation_line_ids.sorted("date")
+        self.assertEqual(lines.mapped("price"), [110.0, 130.0])
+        self.double_item.fixed_price = 200.0
+        self.assertEqual(
+            lines.mapped("price"),
+            [110.0, 130.0],
+            "Prices set on reservations do not follow later changes",
+        )
+        reservation.update_prices()
+        self.assertEqual(lines.mapped("price"), [210.0, 130.0])
+
+    def test_booking_engine_price(self):
+        """The booking engine prices the stay with the derived prices."""
+        total = self.env["pms.folio.availability.wizard"]._get_price_by_room_type(
+            room_type_id=self.superior.id,
+            checkin=self.date,
+            checkout=self.date + datetime.timedelta(days=2),
+            board_service_room_id=False,
+            pricelist_id=self.pricelist1.id,
+            pms_property_id=self.pms_property1.id,
+        )
+        self.assertAlmostEqual(total, 240.0, places=2)
+
+    # Massive changes wizard
+
+    def _massive_changes(self, pricelists, room_types=None, price=50.0):
+        vals = {
+            "massive_changes_on": "pricelist",
+            "pricelist_ids": [(6, 0, pricelists.ids)],
+            "start_date": self.date,
+            "end_date": self.date,
+            "pms_property_ids": [(6, 0, self.pms_property1.ids)],
+            "price": price,
+        }
+        if room_types:
+            vals["room_type_ids"] = [(6, 0, room_types.ids)]
+        return self.env["pms.massive.changes.wizard"].create(vals)
+
+    def _items(self, room_type, pricelist):
+        return self.env["product.pricelist.item"].search(
+            [
+                ("pricelist_id", "=", pricelist.id),
+                ("product_id", "=", room_type.product_id.id),
+                ("date_start_consumption", "=", self.date),
+            ]
+        )
+
+    def test_massive_changes_leave_derived_room_types_out(self):
+        """With no room type selected, derived room types keep following."""
+        self.superior.price_derivation_pricelist_ids = self.pricelist1
+        wizard = self._massive_changes(self.pricelist1 | self.pricelist2)
+        self.assertEqual(wizard.price_derived_room_type_ids, self.superior)
+        wizard.apply_massive_changes()
+        self.assertFalse(self._items(self.superior, self.pricelist1))
+        self.assertAlmostEqual(self._price(self.superior), 60.0, places=2)
+        self.assertTrue(
+            self._items(self.superior, self.pricelist2),
+            "Where it is not derived, the room type gets the price as usual",
+        )
+        self.assertAlmostEqual(
+            self._price(self.superior, pricelist=self.pricelist2), 50.0, places=2
+        )
+
+    def test_massive_changes_keep_overrides(self):
+        """Overrides of derived room types are neither replaced nor removed."""
+        override = self._set_price(self.superior, self.date, 150.0)
+        wizard = self._massive_changes(self.pricelist1)
+        self.assertNotIn(override, wizard.pricelist_items_to_overwrite)
+        self.assertIn(self.double_item, wizard.pricelist_items_to_overwrite)
+        wizard.apply_massive_changes()
+        self.assertTrue(override.exists())
+        self.assertAlmostEqual(self._price(self.superior), 150.0, places=2)
+        self.assertAlmostEqual(self._price(self.double), 50.0, places=2)
+
+    def test_massive_changes_selected_derived_room_type_gets_price(self):
+        """Selecting a derived room type sets a price of its own (override)."""
+        wizard = self._massive_changes(self.pricelist1, room_types=self.superior)
+        self.assertFalse(wizard.price_derived_room_type_ids)
+        wizard.apply_massive_changes()
+        self.assertAlmostEqual(self._price(self.superior), 50.0, places=2)
+        self.assertAlmostEqual(self._price(self.double), 100.0, places=2)
+
+    def test_massive_changes_on_availability_unchanged(self):
+        """Availability changes still apply to every room type."""
+        availability_plan = self.env["pms.availability.plan"].create(
+            {"name": "Availability plan", "pms_pricelist_ids": [self.pricelist1.id]}
+        )
+        wizard = self.env["pms.massive.changes.wizard"].create(
+            {
+                "massive_changes_on": "availability_plan",
+                "availability_plan_ids": [(6, 0, availability_plan.ids)],
+                "start_date": self.date,
+                "end_date": self.date,
+                "pms_property_ids": [(6, 0, self.pms_property1.ids)],
+                "apply_closed": True,
+                "closed": True,
+            }
+        )
+        self.assertFalse(wizard.price_derived_room_type_ids)
+        wizard.apply_massive_changes()
+        self.assertIn(self.superior, availability_plan.rule_ids.room_type_id)
+
+    # Users with access to some properties only
+
+    def _user_env(self, login, pms_property, groups):
+        """The environment of a request of a user of the property only.
+
+        Its cache starts empty, as in a request: values read before by the
+        superuser would hide what the user can read.
+        """
+        user = self.env["res.users"].create(
+            {
+                "name": login,
+                "login": login,
+                "company_id": self.company1.id,
+                "company_ids": [(6, 0, self.company1.ids)],
+                "pms_property_ids": [(6, 0, pms_property.ids)],
+                "pms_property_id": pms_property.id,
+                "groups_id": [(6, 0, [self.env.ref(group).id for group in groups])],
+            }
+        )
+        self.env.invalidate_all()
+        return self.env(
+            user=user,
+            context=dict(self.env.context, allowed_company_ids=self.company1.ids),
+        )
+
+    def _derivation_restricted_to_property1(self):
+        """Room types of all the properties deriving in a rate of property 1.
+
+        The base room type is priced in a rate of property 2, where the derived
+        one does not derive. Users of property 2 cannot read the rate of
+        property 1 the derivation is restricted to.
+        """
+        rate_property1, rate_property2 = self.env["product.pricelist"].create(
+            [
+                {
+                    "name": f"Rate of {pms_property.name}",
+                    "pms_property_ids": [(6, 0, pms_property.ids)],
+                    "availability_plan_id": self.availability_plan1.id,
+                }
+                for pms_property in self.pms_property1 | self.pms_property2
+            ]
+        )
+        double = self._create_room_type(
+            "Shared Double",
+            "PD_SHDBL",
+            list_price=400.0,
+            pms_property_ids=[(6, 0, [])],
+        )
+        superior = self._create_room_type(
+            "Shared Superior",
+            "PD_SHSUP",
+            list_price=300.0,
+            pms_property_ids=[(6, 0, [])],
+            price_base_room_type_id=double.id,
+            price_derivation_value=10.0,
+            price_derivation_pricelist_ids=[(6, 0, rate_property1.ids)],
+        )
+        self._set_price(
+            double,
+            self.date,
+            100.0,
+            pricelist=rate_property2,
+            pms_property=self.pms_property2,
+        )
+        return rate_property2, superior
+
+    def test_restriction_does_not_depend_on_user_access(self):
+        """A restriction to rates the user cannot read is still a restriction.
+
+        Read with the access of the user, it would be empty, i.e. all the
+        pricelists, and the price would depend on who computes it.
+        """
+        rate, superior = self._derivation_restricted_to_property1()
+        self.assertAlmostEqual(
+            self._price(superior, pricelist=rate, pms_property=self.pms_property2),
+            300.0,
+            places=2,
+            msg="Not derived in the rate, the room type gets its list price",
+        )
+        env = self._user_env(
+            "pd_front_desk",
+            self.pms_property2,
+            ["base.group_user", "pms.group_pms_user"],
+        )
+        self.assertAlmostEqual(
+            self._price(
+                superior.with_env(env),
+                pricelist=rate.with_env(env),
+                pms_property=self.pms_property2,
+            ),
+            300.0,
+            places=2,
+        )
+        env.invalidate_all()
+        self.assertFalse(superior.with_env(env)._get_price_derivation(rate))
+
+    def test_massive_changes_do_not_depend_on_user_access(self):
+        """Users leave the same room types out whatever rates they can read."""
+        rate, superior = self._derivation_restricted_to_property1()
+        env = self._user_env(
+            "pd_revenue_manager",
+            self.pms_property2,
+            [
+                "base.group_user",
+                "pms.group_pms_manager",
+                "sales_team.group_sale_manager",
+            ],
+        )
+        wizard = env["pms.massive.changes.wizard"].create(
+            {
+                "massive_changes_on": "pricelist",
+                "pricelist_ids": [(6, 0, rate.ids)],
+                "start_date": self.date,
+                "end_date": self.date,
+                "pms_property_ids": [(6, 0, self.pms_property2.ids)],
+                "price": 50.0,
+            }
+        )
+        self.assertFalse(wizard.price_derived_room_type_ids)
+        wizard.apply_massive_changes()
+        self.assertAlmostEqual(
+            self._price(superior, pricelist=rate, pms_property=self.pms_property2),
+            50.0,
+            places=2,
+            msg="Not derived in the rate, the room type gets the price as usual",
+        )
+
+    def test_too_many_levels_beyond_user_access(self):
+        """Room types the user cannot read count for the levels as well."""
+        root = room_type = self._create_room_type(
+            "Shared Level 0", "PD_SHL0", pms_property_ids=[(6, 0, [])]
+        )
+        for level in range(1, 10):
+            room_type = self._create_room_type(
+                f"Shared Level {level}",
+                f"PD_SHL{level}",
+                pms_property_ids=[(6, 0, [])],
+                price_base_room_type_id=room_type.id,
+            )
+        # Of property 1, out of the access of the users of property 2
+        self._create_room_type(
+            "Level 10", "PD_SHL10", price_base_room_type_id=room_type.id
+        )
+        new_root = self._create_room_type(
+            "Shared Root", "PD_SHROOT", pms_property_ids=[(6, 0, [])]
+        )
+        env = self._user_env(
+            "pd_manager",
+            self.pms_property2,
+            ["base.group_user", "pms.group_pms_manager"],
+        )
+        with self._assert_refused(ValidationError, "too many levels"):
+            root.with_env(env).price_base_room_type_id = new_root
+
+    # Translations
+
+    def test_spanish_translations(self):
+        """The new labels and messages are translated into Spanish."""
+        self.env["res.lang"]._activate_lang("es_ES")
+        self.env.ref("base.module_pms")._update_translations(["es_ES"])
+        env_es = self.env(context=dict(self.env.context, lang="es_ES"))
+        self.assertEqual(
+            env_es["ir.model.fields"]
+            ._get("pms.room.type", "price_base_room_type_id")
+            .field_description,
+            "Precio derivado de",
+        )
+        left_out = env_es["ir.model.fields"]._get(
+            "pms.massive.changes.wizard", "price_derived_room_type_ids"
+        )
+        self.assertEqual(left_out.field_description, "Excluidos (precio derivado)")
+        self.assertIn("precio propio, que se mantiene", left_out.help)
+        self.assertIn("Selecciónelos expresamente", left_out.help)
+        self.assertIn(
+            "Déjelo vacío",
+            env_es["ir.model.fields"]
+            ._get("pms.room.type", "price_derivation_pricelist_ids")
+            .help,
+        )
+        arch = env_es["pms.room.type"].get_view(
+            self.env.ref("pms.pms_room_type_view_form").id, "form"
+        )["arch"]
+        self.assertIn("Precio derivado", arch)
+        with self._assert_refused(ValidationError, "sí mismo"):
+            self.double.with_env(env_es).price_base_room_type_id = self.superior
+        with self._assert_refused(UserError, "demasiados niveles"):
+            self._price(
+                self.superior.with_env(env_es),
+                pricelist=self.pricelist1.with_env(env_es),
+                price_derivation_depth=10,
+            )
diff --git a/pms/tests/test_view_check_pms_properties.py b/pms/tests/test_view_check_pms_properties.py
index dea884522a..f20ec0fbde 100644
--- a/pms/tests/test_view_check_pms_properties.py
+++ b/pms/tests/test_view_check_pms_properties.py
@@ -30,6 +30,7 @@ class TestViewCheckPmsProperties(common.TransactionCase):
         "pms.product_pricelist_item_view_form",
         "pms.product_template_view_form",
         "pms.res_partner_view_form",
+        "pms.pms_room_type_view_form",
     ]
 
     def test_views_validate_with_injected_property_domain(self):
diff --git a/pms/views/pms_room_type_views.xml b/pms/views/pms_room_type_views.xml
index a58b67c87c..22ab3021d0 100644
--- a/pms/views/pms_room_type_views.xml
+++ b/pms/views/pms_room_type_views.xml
@@ -41,6 +41,34 @@
                             <field name="categ_id" />
                         </group>
                     </group>
+                    <group name="price_derivation_group" string="Derived Price">
+                        <group>
+                            <field
+                                name="price_base_room_type_id"
+                                options="{'no_create': True}"
+                            />
+                            <field
+                                name="price_derivation_type"
+                                attrs="{'invisible': [('price_base_room_type_id', '=', False)]}"
+                            />
+                            <field
+                                name="price_derivation_value"
+                                attrs="{'invisible': [('price_base_room_type_id', '=', False)]}"
+                            />
+                            <field
+                                name="price_derivation_rounding"
+                                attrs="{'invisible': ['|', ('price_base_room_type_id', '=', False), ('price_derivation_type', '!=', 'percent')]}"
+                            />
+                        </group>
+                        <group>
+                            <field
+                                name="price_derivation_pricelist_ids"
+                                widget="many2many_tags"
+                                options="{'no_create': True}"
+                                attrs="{'invisible': [('price_base_room_type_id', '=', False)]}"
+                            />
+                        </group>
+                    </group>
                     <notebook>
                         <page string="Board Services">
                             <separator string="Board Services" />
@@ -91,6 +119,7 @@
                 <field name="name" />
                 <field name="default_code" />
                 <field name="list_price" />
+                <field name="price_base_room_type_id" optional="hide" />
                 <field name="room_ids" widget="many2many_tags" />
                 <field name="total_rooms_count" />
             </tree>
diff --git a/pms/wizards/wizard_massive_changes.py b/pms/wizards/wizard_massive_changes.py
index afa05de7e2..d001b802cb 100644
--- a/pms/wizards/wizard_massive_changes.py
+++ b/pms/wizards/wizard_massive_changes.py
@@ -65,11 +65,24 @@ class AvailabilityWizard(models.TransientModel):
     room_type_ids = fields.Many2many(
         comodel_name="pms.room.type",
         string="Room Type",
+        help="Room types to apply the changes to. Leave it empty to apply them "
+        "to all the room types of the properties, except for the prices of the "
+        "room types whose price is derived from another one",
         check_pms_properties=True,
         compute="_compute_room_type_ids",
         readonly=False,
         store=True,
     )
+    price_derived_room_type_ids = fields.Many2many(
+        string="Left Out (Derived Price)",
+        help="Room types whose price is derived from another one in the selected "
+        "pricelists. As no room type is selected, the new price is not set on "
+        "them: they keep following the room type their price is derived from, "
+        "except on the dates they have a price of their own, which is kept. "
+        "Select them explicitly to give them a price of their own",
+        comodel_name="pms.room.type",
+        compute="_compute_price_derived_room_type_ids",
+    )
 
     board_service_room_type_ids = fields.Many2many(
         string="Room type's board services",
@@ -279,6 +292,48 @@ def _compute_room_type_ids(self):
             ):
                 record.room_type_ids = False
 
+    @api.depends(
+        "massive_changes_on",
+        "apply_pricelists_on",
+        "room_type_ids",
+        "pricelist_ids",
+        "pms_property_ids",
+    )
+    def _compute_price_derived_room_type_ids(self):
+        for record in self:
+            # The pricelist the wizard is opened from may not be set yet
+            pricelists = record.pricelist_ids or self.env["product.pricelist"].browse(
+                self._context.get("pricelist_id")
+            )
+            room_types = self.env["pms.room.type"]
+            for pricelist in pricelists:
+                room_types |= record._get_price_derived_room_types(pricelist)
+            record.price_derived_room_type_ids = room_types.filtered(
+                lambda room_type, record=record: not room_type.pms_property_ids
+                or room_type.pms_property_ids & record.pms_property_ids
+            )
+
+    def _get_price_derived_room_types(self, pricelist):
+        """Room types left out of the price changes on the pricelist.
+
+        With no room type selected, prices are set on all the room types of the
+        properties but on the ones whose price is derived in the pricelist: an
+        item of their own would be an override and they would no longer follow
+        their base room type. Selecting them explicitly sets it anyway.
+        """
+        self.ensure_one()
+        if (
+            self.massive_changes_on != "pricelist"
+            or self.apply_pricelists_on != "room_types"
+            or self.room_type_ids
+        ):
+            return self.env["pms.room.type"]
+        return (
+            self.env["pms.room.type"]
+            .search([("price_base_room_type_id", "!=", False)])
+            ._get_price_derivation(pricelist)
+        )
+
     @api.depends("apply_pricelists_on", "board_service")
     def _compute_board_service_room_type_ids(self):
         for record in self:
@@ -536,7 +591,9 @@ def _compute_pricelist_items_to_overwrite(self):
                 )
 
                 if record.start_date and record.end_date:
-                    items = self.env["product.pricelist.item"].search(domain)
+                    items = record._exclude_price_derived_items(
+                        self.env["product.pricelist.item"].search(domain)
+                    )
                     if (
                         not record.apply_on_all_week
                         and record.start_date
@@ -562,6 +619,21 @@ def _compute_pricelist_items_to_overwrite(self):
             else:
                 record.pricelist_items_to_overwrite = False
 
+    def _exclude_price_derived_items(self, items):
+        """Keep the items of the room types left out of the price changes.
+
+        Those are overrides of a derived price set on purpose: the changes
+        neither replace nor remove them (see _get_price_derived_room_types).
+        """
+        self.ensure_one()
+        derived_products = {
+            pricelist: self._get_price_derived_room_types(pricelist).product_id
+            for pricelist in items.pricelist_id
+        }
+        return items.filtered(
+            lambda item: item.product_id not in derived_products[item.pricelist_id]
+        )
+
     @api.depends(
         "rules_to_overwrite",
     )
@@ -869,6 +941,10 @@ def apply_massive_changes(self):
             self.apply_on_saturday,
             self.apply_on_sunday,
         )
+        price_derived_room_types = {
+            pricelist: self._get_price_derived_room_types(pricelist)
+            for pricelist in self.pricelist_ids
+        }
 
         # dates between start and end (both included)
         items = []
@@ -898,16 +974,17 @@ def apply_massive_changes(self):
                     self.massive_changes_on == "pricelist"
                     and self.apply_pricelists_on == "room_types"
                 ):
-                    new_items = self.create_pricelists_items_room_types(
-                        room_types,
-                        self.pricelist_ids,
-                        self.price,
-                        self.min_quantity,
-                        pms_property,
-                        date,
-                        self.date_types,
-                    )
-                    items = items + new_items if new_items else items
+                    for pricelist in self.pricelist_ids:
+                        new_items = self.create_pricelists_items_room_types(
+                            room_types - price_derived_room_types[pricelist],
+                            pricelist,
+                            self.price,
+                            self.min_quantity,
+                            pms_property,
+                            date,
+                            self.date_types,
+                        )
+                        items = items + new_items if new_items else items
 
                 elif (
                     self.massive_changes_on == "pricelist"
diff --git a/pms/wizards/wizard_massive_changes.xml b/pms/wizards/wizard_massive_changes.xml
index a8762827e0..9018c1cc25 100644
--- a/pms/wizards/wizard_massive_changes.xml
+++ b/pms/wizards/wizard_massive_changes.xml
@@ -67,6 +67,12 @@
                                 options="{'no_create': True,'no_open': True}"
                                 attrs="{'invisible':[('apply_pricelists_on','!=','room_types'),('massive_changes_on', '=','pricelist')],'required': []}"
                             />
+                            <field
+                                name="price_derived_room_type_ids"
+                                widget="many2many_tags"
+                                options="{'no_create': True,'no_open': True}"
+                                attrs="{'invisible':[('price_derived_room_type_ids', '=', [])]}"
+                            />
                             <field
                                 name="board_service_room_type_ids"
                                 widget="many2many_tags"