Measured on our floor: the nmax2 drafter inverts acceptance against the draft-12 control — 72.2% vs 22.7% — with the control at 17.5 tok/s and nmax2-np2 at 25.4 (nmax3 28.5, nmax4 23.9). Engine verdict: HIP 20.8 tok/s over Vulkan 9.2 on the same box.
Every figure is dual-verified (receipt: research/floor-optimization/window4/W4-VERIFICATION-RECEIPT-20260925.md). The acceptance inversion leads because it is the question the field is actively confused by.
Limits: single lab, single box-class, our workloads. No external reproduction claimed.