Constant AWAIT_STEP 

const AWAIT_STEP: i64 = _; // 300_000i64

The most one exchange counts of the wait (AWAITED): the time since the one before, five minutes at most (milliseconds). A device asleep, or closed, counts none of that time: woken, its sync app may not have brought the round’s end yet, and passing the round over then would ask for a full round for nothing (on a phone, megabytes of its texts: review of 10 October 2026, third pass).