measurement surface: raw
arm                            n  in-band  on-beat   cover  ran-on  words
-------------------------------------------------------------------------
base                         240     0.89     0.71    0.63    0.01    110
ckpt900                      240     0.67     0.42    0.44    0.28    114
ckpt450                      240     0.67     0.45    0.44    0.20    108
ckpt300                      240     0.65     0.42    0.43    0.13    102
ckpt225                      240     0.52     0.43    0.45    0.38    126

noise floor (max within-arm spread across seeds): 0.200
⚠ any between-arm gap at or under that is NOT a finding

1. in-band  0.52 vs 0.89  delta -0.37  FAIL  (needs > +0.200)
2. on-beat  0.43 vs 0.71  delta -0.29  FAIL  (needs >= -0.200)
3. ran-on   0.38 vs 0.01  delta +0.37  FAIL  (needs <= +0.200)

VERDICT: DO-NOT-SCALE