Before comparing a client end-to-end reading with a server processing reading, resolve their actual Characteristic and observation basis. Both may use ms yet answer different questions. Keep separate coordinates or obtain readings for the same declared characteristic and basis; a unit conversion alone cannot supply that match.
normalization: monotone time‑warp compensation for collector skew; invariant = percentile order
comparability: normalization‑based (UNM) with declared normalization
aggregation: use a max-of-mins latency fold only when the declared service model justifies it; a WLNK bound needs its own bottleneck model. Neither follows from latency percentiles alone.
RSG hook: DeployerRole.Active gated if P99 < declared SLO over the admission window.