Fixed units do not mean hypothesis-dependent apparatus

A physical split filter below contains the coefficient

with units of inverse length squared. Changing the bookkeeping length $\sigma$ requires $\chi \mapsto \eta {\sigma }^2$ to keep the same apparatus. Holding $\chi$ fixed while setting $\sigma ={\xi }_h$ separately for the hypotheses changes the physical measurement.

The same principle applies to sensor strength, curvature, duration, acceptance windows, phase compensation, and electronic response. They are setting specifications, not quantities that may be silently redefined using the unknown hypothesis.