diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe377f8..fa0a30f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -139,7 +139,12 @@
   2.39 → 1.94–2.04 µs (−17%); group B-tree walk 405–411 → 322–351 ns
   (−16%); listing the 400-group file through the facade 8.56–8.71 →
   8.40–8.42 ms (−2.4%). Net, local metadata reads are slightly faster; the
-  per-header cost is a known, small regression.
+  per-header cost is a known, small regression. Data reads are unchanged:
+  `concurrent_read --decode-threads 1` (the `BENCHMARKS.md` "Concurrent
+  reads" workload), `main` and this branch alternating, 2 rounds each, on
+  the same idle start: every deflate and contiguous full-read row within
+  ±2.4% of `main` (the cache-bound contiguous hyperslab rows vary by up to
+  ±40% between `main`'s own rounds and are not comparable).
 - New equivalence harness `clawhdf5-format/tests/storage_equivalence.rs`:
   every converted parser runs over the file as a slice and over
   `storage::CountingStorage` — a `Storage` that serves an in-memory buffer