RAN engineers inherit a 'maintenance window' from the OSS calendar and assume it is the safe time to act. It usually is not. The window is a contractual convenience; the real safety margin is the traffic trough for the specific cell or cluster you are touching, which drifts by timezone, by site type (residential vs. transit-corridor vs. stadium), and by day of week. A residential macro troughs around 03:00; a highway small cell may never trough below 40% PRB.
The operational insight is to query per-cell utilization for the target sites and schedule against the measured trough, not the global window. An agent applying this pulls the last 7 days of PRB and RRC-connected-user counters, finds the per-site minimum, and stages the change list ordered by trough time so each cell is touched when it is genuinely quiet. A single batch may therefore span several sub-windows rather than firing all at once.
Caveat: troughs collapse during events and holidays, and a cell freshly added to a cluster has no history to trough against — fall back to the conservative global window when the 7-day signal is missing or anomalous.