diff --git a/docs/formats/core-data-regions.md b/docs/formats/core-data-regions.md
index ce97e3d..4c8557f 100644
--- a/docs/formats/core-data-regions.md
+++ b/docs/formats/core-data-regions.md
@@ -592,7 +592,28 @@ explaining the other. Recorded as an open discrepancy rather than resolved in
 favour of either: the marker spacing says 12, the period says 40, and 40 being
 twice as strong is the more surprising of the two.
 
-This is the first place in this project where two sound measurements of the
-same data point at incompatible answers. Worth resolving before any record
-layout is attempted, because a layout built on the wrong one will parse
-plausibly and be wrong.
+### Resolved: 40 is the record, the 12-byte markers are nested
+
+A fine scan settles it in favour of 40.
+
+| stride | excess |
+|---|---|
+| **40** | **+0.454** |
+| 39 | +0.266 |
+| 41 | +0.215 |
+| 38 | +0.214 |
+
+The peak is sharp and isolated -- nearly twice its immediate neighbours.
+And the multiples confirm it: 80 scores +0.376, 120 +0.394, 160 +0.340,
+while the multiples of 12 (24, 48, 96, 144) all sit at 0.21-0.24.
+
+So the record is **40 bytes**, and the `0x7f`/`0x47f` markers at 12-byte
+spacing are a nested structure *inside* those records rather than the record
+boundary. Their spacing is irregular -- 12, 24 and larger -- which is exactly
+what one would expect of a field that is present in some records and absent in
+others.
+
+The earlier "they disagree" framing was wrong in one respect: the marker
+spacing never claimed to be the record size. Read as a claim about markers
+inside records rather than about the record itself, the two measurements were
+never in conflict.