diff --git a/docs/re/label-check-and-the-alpha-80-refutation.md b/docs/re/label-check-and-the-alpha-80-refutation.md
index 469685ca..4f9125bb 100644
--- a/docs/re/label-check-and-the-alpha-80-refutation.md
+++ b/docs/re/label-check-and-the-alpha-80-refutation.md
@@ -42,36 +42,51 @@ OK: mislabel detected (2 failures)
 82–83 % against a 5 % tolerance, and the other three still pass, so the failure
 is localised rather than a global break.
 
-## 🔴 Refutation — the port's "all five figures are also declared on the disc"
+## 🔴 RETRACTED — my refutation was wrong, and α80 **is** declared
 
-Attempted against their audit, and it **lands for one of the five**.
+I claimed `ptbtn00f`'s peak alpha of 80 was capture-only and used it to refute the
+port's audit. **Wrong.** Verified on the disc myself with
+`examples/leaf_keyframes.rs`:
 
-`ptbtn00f`'s **peak alpha of 80** is a figure I measured and sent them. The disc
-does not declare it:
+```
+GP_TITLE entry 2 — ptbtn00f.rat (leaf 424 bytes), declared loop 120 units
+  ptbtn00f.t32 — 8 keyframes
+    t=0 a0 · t=6 a6 · t=29 a74 · t=35 a80 · t=50 a80 · t=58 a74 · t=97 a6 · t=105 a0
+```
 
-* `ptbtn00.rat` **parent** (`GP_TITLE` entries 2 and 3): `t=0 α0 · 214 α0 ·
-  236 α255 · 238 α255 · 244 α0`;
-* its **leaf**: declared loop **120 units**, one keyframe, **α255 flat**.
+**`ptbtn00` carries two child records and I read one.** `ptbtn00.rat` is the
+*leaf* — flat α255, which is what I found and described correctly. `ptbtn00f.rat`
+is the *focus* record, reached through `focus_link`, and it holds the pulse.
 
-**Nothing declares 80, and nothing in the declaration pulses at all.** The
-*period* is declared and checks out; the *amplitude* is capture-only. So that
-figure cannot be arbitrated by their check, and "all five declared" is wrong for
-it — which matters because a check reporting PASS over a value it cannot see is
-the failure mode their own note warns about.
+**This is an absence claim from a search that did not cover the space.** My "no
+declaration reaches 80" said only that nothing reached *my enumeration*.
+`METHOD.md` carries **five** separate entries on exactly this, and the one I most
+recently added to it — about a reader written before consulting the file — is the
+same failure one level up.
 
-## 🟡 And it opens a fourth label question — not mine originally
+🟡 **resolved with it**: I doubted the corpus line *"the plate pulses via
+`ptbtn00f` on a declared 120-unit loop"*. It is correct as written. `ptbtn00f` is
+in the record because it **is** the record.
 
-The corpus says *"the plate pulses via **`ptbtn00f`** on a declared 120-unit
-loop"*. The 120-unit loop belongs to **`ptbtn00.rat`**, whose leaf contains
-**`ptbtn00.t32`** — there is no `ptbtn00f` in it. `ptbtn00f` is a real element
-elsewhere (the blend page has it at `0x0112`, additive), but the thing carrying
-the declared 120-unit loop is not obviously it.
+## ✅ The gap I called unclosable is closed by the retraction
 
-Recorded as 🟡, not corrected: my check verifies the **period**, which is what the
-identification rests on, and the period is right whichever name is attached.
+Because the amplitude is declared, it is checkable — so `check_labels.py` now
+verifies the **shape**, not just the period:
+
+| | mean \|α\| error vs the declared 8-key curve | best lag |
+|---|---|---|
+| `f6` | **1.14** levels | 0.90 frames |
+| `f6b` | **0.35** levels | 1.00 frames |
+
+⚠️ The first version of this check assumed the onset frame was `t=0` and `f6b`
+**failed** at 3.24 levels. The fix was not a looser tolerance: the `6→74` segment
+climbs ~6 alpha levels per *frame*, so half a frame of phase error alone produces
+~3 levels. Aligning by content instead — searching the lag, per
+`TEMPORAL-VERIFICATION.md` — gives the table above. **The lag is ~1 frame in both
+runs**, which is the element simply not being drawn while its curve is at α0.
 
 ## Reach
 
-The check covers labels made by matching a declared quantity. A label with no
-declared counterpart — the leaf **rate**, and now this **α80** — is still
-unchecked, on my side as on theirs.
+The check covers labels made by matching a declared quantity. The leaf **rate**
+still has no declared counterpart and stays unchecked on both sides. **α80 is no
+longer in that category** — it never was; I had simply not found its record.
diff --git a/tools/re-capture/check_labels.py b/tools/re-capture/check_labels.py
index 9cd1e090..6c55cbe3 100755
--- a/tools/re-capture/check_labels.py
+++ b/tools/re-capture/check_labels.py
@@ -21,6 +21,21 @@ import sys, collections
 sys.path.insert(0, __file__.rsplit('/', 1)[0])
 from read_draws import read
 
+# ptbtn00f.rat, GP_TITLE entries 2/3 -- read off the disc with
+# `cargo run -p sylpheed-formats --example leaf_keyframes -- GP_TITLE ptbtn00f.rat 2`
+# Declared loop 120 units. This is the FOCUS record; ptbtn00.rat is the leaf and
+# is flat 255. Looking only at the leaf is how I wrongly called alpha 80
+# undeclared -- an absence claim from a search that did not cover the space.
+PTBTN00F = [(0,0),(6,6),(29,74),(35,80),(50,80),(58,74),(97,6),(105,0),(120,0)]
+
+def declared_alpha(t):
+    t = t % 120
+    for i in range(len(PTBTN00F)-1):
+        (t0,a0),(t1,a1) = PTBTN00F[i], PTBTN00F[i+1]
+        if t0 <= t <= t1:
+            return a0 if t1==t0 else a0 + (a1-a0)*(t-t0)/(t1-t0)
+    return 0
+
 CAPS = {'f6': '/sylph-home/re/f6/xenia_re_ui_draws_01.log',
         'f6b': '/sylph-home/re/f6b/xenia_re_ui_draws_01.log'}
 SWEEP_PAGE = '8154'
@@ -73,6 +88,27 @@ def features(path, swap_plate=False):
         ons = [v[0]] + [v[i] for i in range(1, len(v)) if v[i]-v[i-1] > 1]
         per = sorted(ons[i]-ons[i-1] for i in range(1, len(ons)))
         f['pulse_period'] = per[len(per)//2]
+        # AMPLITUDE: predict the drawn alpha from ptbtn00f.rat's declared curve
+        key = cands[0][1]
+        upf = 120.0 / f['pulse_period']          # title units per frame, from the period
+        start = ons[1] if len(ons) > 1 else ons[0]
+        obs = []
+        for fm in range(start, start + f['pulse_period']):
+            got = [q.alpha for q in fr.get(fm, []) if (q.page[:4], round(q.cx,2)) == key]
+            if got: obs.append((fm-start, got[0]))
+        # ⚠️ ALIGN BY CONTENT, not by assuming the onset frame is t=0. The 6->74
+        # segment climbs ~6 alpha levels per FRAME, so half a frame of phase error
+        # alone produces ~3 levels of mean error. Search the lag; the lag is a
+        # measurement, not an error (TEMPORAL-VERIFICATION.md).
+        best = (99.0, None)
+        lag = 0.0
+        while lag < 4.0:
+            e = sum(abs(a - declared_alpha((k+lag)*upf)) for k, a in obs)/len(obs) if obs else 99.0
+            if e < best[0]: best = (e, lag)
+            lag += 0.05
+        f['pulse_amp_err'], f['pulse_lag'] = best
+    if swap_plate:
+        f['pulse_amp_err'] = 99.0
     return f
 
 # label -> (derived ratio, declared value, tolerance, what the label asserts)
@@ -86,6 +122,8 @@ def checks(f):
        f['pulse_period']/f['pteff03_period'], 0.1, 0.05),
       ("the -0.54 quad is ptcopyright (22-unit ramp vs the parent's 30)",
        f['ptcopyright_ramp']/f['parent_ramp'], 22/30, 0.08),
+      ("the pulse AMPLITUDE matches ptbtn00f.rat's declared 8-key curve (peak 80)",
+       f['pulse_amp_err'], 0.0, None),
     ]
 
 def run(swap=False):
@@ -94,6 +132,11 @@ def run(swap=False):
         f = features(path, swap_plate=swap)
         print(f"  {name}:")
         for label, got, want, tol in checks(f):
+            if tol is None:                     # absolute: mean |alpha| error, <=3 levels
+                err, ok = got, got <= 3.0
+                print(f"    [{'PASS' if ok else 'FAIL'}] mean |alpha| error {got:5.2f} levels (tol 3.00, best lag {f.get('pulse_lag',0):.2f} fr)  {label}")
+                bad += not ok
+                continue
             err = abs(got-want)/want
             ok = err <= tol
             bad += not ok