Function is_peak 

pub fn is_peak(at_ms: i64) -> bool

Is this instant inside a DeepSeek peak window?

The docs give it exactly: 01:00–04:00 and 06:00–10:00 UTC, Monday–Friday; every other hour, weekends included, is off-peak. The console applies it (its per-request cost for a peak-hour turn is the peak sheet), while opencode records the off-peak sheet for every turn — which is why this store reads ~40% under the console on peak-heavy days and why the total is priced here instead of trusting cost.