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

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  0.67 vs 0.89  delta -0.22  FAIL  (needs > +0.200)
2. on-beat  0.42 vs 0.71  delta -0.29  FAIL  (needs >= -0.200)
3. ran-on   0.28 vs 0.01  delta +0.27  FAIL  (needs <= +0.200)

VERDICT: DO-NOT-SCALE