Retries now land at the right time of day
Pin each retry to a set clock time and it fires on the right day, whatever hour the first call went out.
Set the exact time each retry goes out
Pick a clock time for each retry, like 10:00 or 16:00, and it fires on the right day no matter when the first call started. Retries that would land outside 09:00 to 19:00 are skipped instead of pushed to odd hours.