diff --git a/.cargo/mutants.toml b/.cargo/mutants.toml
index c2316a8..2fbac63 100644
--- a/.cargo/mutants.toml
+++ b/.cargo/mutants.toml
@@ -130,12 +130,45 @@ exclude_re = [
     # not pay the timeout floor weekly for a verdict already in hand.
     "otel\\.rs:931:21:.*\\+= with \\*=",
     "otel\\.rs:634:22:.*== with !=",
+    # The quicksearch byte scanners' cursor hangs, hand-reproduced test by
+    # test under a 10s timeout: `i *= 1` leaves the index where it is, so
+    # the loop re-runs the same byte in the same state forever; `i -= 1`
+    # (`-= 2` past an escape) steps back onto a byte the preceding branch
+    # advances over again, so the pair cycles (on other inputs it
+    # underflows, and those tests fail). Each one hangs at least one test
+    # in the same binary, which then never exits, so no added test can
+    # turn it into a kill.
+    "server\\.rs:2044:15:.*\\+= with -=",
+    "server\\.rs:2052:15:.*\\+= with (-=|\\*=)",
+    "server\\.rs:2063:15:.*\\+= with \\*=",
+    "server\\.rs:2078:15:.*\\+= with (-=|\\*=)",
+    "server\\.rs:2082:11:.*\\+= with (-=|\\*=)",
+    "server\\.rs:2099:11:.*\\+= with \\*=",
+    "server\\.rs:2116:15:.*\\+= with (-=|\\*=)",
+    "server\\.rs:2132:11:.*\\+= with (-=|\\*=)",
+    "server\\.rs:2144:11:.*\\+= with \\*=",
+    # The foreign-host skip `at = pos + 1`: `pos - 1` and `pos * 1` both
+    # re-find the occurrence just rejected, so the scan never passes it
+    # (embedded_scan_needs_a_domain_boundary_on_the_left hangs).
+    "guard\\.rs:942:26:.*\\+ with (-|\\*)",
+    # The stdio delimiter advance `newline + 1` (DESIGN.md): `- 1` and
+    # `* 1` leave the newline inside `rest`, so the frame loop finds it
+    # again forever (the multi-frame drain hangs; `- 1` on a bare newline
+    # underflows instead, in the same binary).
+    "stdio\\.rs:196:34:.*\\+ with (-|\\*)",
     # The glob backtrack advance is unobservable: `p = star_pos` re-enters
     # the `'*'` arm and lands on the identical (p, resume, s) state one
     # iteration later (or skips the same `'*'` in the trailing-star loop),
     # proven by 265k exhaustive + 200k random differential cases with zero
     # divergences.
     "policy\\.rs:171:26:.*\\+ with \\*",
+    # Its three advances frozen by `*= 1` — the `'*'` skip (164), the
+    # backtrack resume (172) and the trailing-star drain (180) — never
+    # move p or resume, so every glob test with a `*` hangs; reproduced
+    # by hand like the otel hangs above.
+    "policy\\.rs:164:15:.*\\+= with \\*=",
+    "policy\\.rs:172:20:.*\\+= with \\*=",
+    "policy\\.rs:180:11:.*\\+= with \\*=",
     # Typo-shaped ports are refused by exact refusal text the anchor tests
     # pin; `>=` for `>` is identical (at equal lengths the byte lookup is
     # None), so that one is documented in DESIGN.md, not tested.
diff --git a/.github/workflows/mutants.yml b/.github/workflows/mutants.yml
index 0a784c0..e9738bd 100644
--- a/.github/workflows/mutants.yml
+++ b/.github/workflows/mutants.yml
@@ -87,8 +87,9 @@ jobs:
       # the tier/variant/tag exclusions, policy.rs the glob-advance one,
       # client.rs none; the eight small files carry two
       # documented-not-tested exclusions (config port >=, custom comma
-      # collapse) while the stdio delimiter hangs stay in scope and pay
-      # the floor weekly.
+      # collapse). Hand-reproduced cursor hangs (server, policy, guard,
+      # stdio) are excluded like otel's, so a verdict already in hand does
+      # not pay the floor weekly.
       MUTANTS_SCOPE: crates/bugwarden-core/src/guard.rs crates/bugwarden/src/main.rs crates/bugwarden/src/server.rs crates/bugwarden/src/audit.rs crates/bugwarden/src/otel.rs crates/bugwarden-core/src/client.rs crates/bugwarden-core/src/policy.rs crates/bugwarden-core/src/custom_fields.rs crates/bugwarden/src/config.rs crates/bugwarden/src/http_auth.rs crates/bugwarden/src/stdio.rs crates/bugwarden/src/tracing_fields.rs crates/bugwarden/src/http_session.rs crates/bugwarden/src/panic_hook.rs crates/bugwarden-core/src/quoted.rs
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
diff --git a/crates/bugwarden-core/src/client.rs b/crates/bugwarden-core/src/client.rs
index b2038f8..86bb7c2 100644
--- a/crates/bugwarden-core/src/client.rs
+++ b/crates/bugwarden-core/src/client.rs
@@ -1047,4 +1047,24 @@ mod tests {
             "Debug keeps the status and the code: {own}"
         );
     }
+
+    /// Microseconds are summed across requests and reported as whole
+    /// milliseconds, so two sub-millisecond waits make one together; a `%`
+    /// or `*` in the scale reports 300 or 1_300_000 for the same pair.
+    #[test]
+    fn upstream_stats_sum_microseconds_into_whole_milliseconds() {
+        let stats = UpstreamStats::default();
+        stats.record(Duration::from_micros(600), Some(200));
+        stats.record(Duration::from_micros(700), None);
+        assert_eq!(stats.requests(), 2);
+        assert_eq!(stats.latency_ms(), 1);
+        assert_eq!(
+            stats.status(),
+            None,
+            "the last request produced no response"
+        );
+        stats.record(Duration::from_micros(2_345_678), Some(404));
+        assert_eq!(stats.latency_ms(), 2_346);
+        assert_eq!(stats.status(), Some(404));
+    }
 }
diff --git a/docs/DESIGN.md b/docs/DESIGN.md
index f692957..fe9dcb5 100644
--- a/docs/DESIGN.md
+++ b/docs/DESIGN.md
@@ -3957,8 +3957,11 @@ wired, `server.rs` and `main.rs` are the reference.
   Display is the unchanged text; the code is read only inside an
   `"error": true` envelope (a proxy's non-2xx JSON, a string code and a float
   code give none); a gateway's HTML under 502 and a 200 non-JSON body are
-  typed with no code; and neither the type's Debug nor anyhow's alternate
-  Debug carries the message.
+  typed with no code; neither the type's Debug nor anyhow's alternate
+  Debug carries the message; and `UpstreamStats` sums microseconds across
+  requests into whole milliseconds (two sub-millisecond waits make one, so
+  neither a `%` nor a `*` scale passes), the last status winning and a
+  response-less request reading `None`.
 - Unit tests (#[cfg(test)] in crates/bugwarden/src/server.rs): assemble_bug_info
   re-classification — a body embargoed after the verdict is refused, a body
   that now earns only summary is downgraded, a body granting neither read nor