V86: Why 8.4% Is Not Small — A Variance-First Unification of Cluster Detection and Micro-Scale Resolution in YAGC

V85 produced a falsifiable cluster benchmark: at fixed mass, dynamically active (merging) clusters should exhibit a ~8.4% temperature enhancement relative to relaxed clusters. Simultaneously, V85 flagged a "detected inconsistency" when the same update-density engine was applied to the microscopic generation sector. V86 demonstrates that these two outcomes are the same problem viewed through one lens: variance-first physics (V65). The 8.4% is not "small"; it is a variance signal that becomes visible only after breaking mass–activity degeneracy with lensing-calibrated masses and controlled temperature definitions. The micro mismatch is not an engine failure; it is a failure to define an appropriate micro-scale activity (variance) variable. By testing three candidate definitions—(i) decay width Γ (instability), (ii) channel diversity (entropy), and (iii) running/scale-dependence—we find that only instability Γ aligns with the YAGC saturation-node claim (top quark near saturation) and restores conceptual continuity with the ρ(A) engine. V86 provides a single, clean answer: YAGC effects hide where averages absorb variance, and appear where variance is preserved or properly defined. This paper includes power analysis, mass error propagation studies, statistical robustness tests, and explicit failure conditions for both macro and micro sectors.