diff --git a/docs/port/HANDOFF.md b/docs/port/HANDOFF.md
index f149a9e7..ce5b2b29 100644
--- a/docs/port/HANDOFF.md
+++ b/docs/port/HANDOFF.md
@@ -6032,3 +6032,27 @@ reproduced 4/4, so that page's "retry whole boots" does not obviously apply.
 
 Detail: [`docs/re/structures/title-a-press-fault.md`](../re/structures/title-a-press-fault.md).
 
+
+## F6 answered — the sweep leads the plate, and frame counts don't travel
+
+`docs/re/f6-unit9-sweep-period-and-onset.md`, commit `ad83664`.
+
+**Start the sweep shortly before the plate's fade-in, not at `t=0`.** At `t=0` it
+is ~200 title units early. Measured lead: **0.798 / 0.791 baselines** across two
+independent captures (0.9% apart) ≈ **40 title units** — under a second, which is
+why the human read the sweep and the plate as simultaneous. Loop period is
+**13.93 baselines** (13.905 / 13.953, 0.35% apart).
+
+⚠️ **Any rate I have given in captured frames is withdrawn.** The same animation
+took **1168** frames in one capture and **600** in the other (**1.947×**), the
+baseline moving **1.953×** with it — frames are presents and the rate is per-run.
+That includes unit 8's **0.514 units/frame**: a 1.95× run-to-run factor is
+exactly the size of the port-vs-decoder gap we could not explain, so the 0.514
+was most likely a pacing artefact of one capture. The port running the leaf at
+1.0× is not the discrepancy it looked like.
+
+🟡 Unresolved and deliberately not smoothed: within one capture the title clock
+reads **1.0 units/frame** (`ptcopyright`, 22-unit ramp) and **0.571** (plate,
+declared 12-unit ramp) — 1.75× apart. Either a declared ramp is misread or the
+two are **not on one clock**, i.e. `clock: "shared"`. That is F4. Ratios above
+need no clock and stand; the title-unit conversions wait on it.