Running v3.2.1, in Server Config I changed the backup time from 00:00 to 17:00. The backup is still done at 00:00. I was experimenting with this, for example at 16:10 I changed the time to 16:30 and waited, no backup. Did that a few times with no change. In this exercise I changed the destination backup directory and that did work. So it's not that it's not loading new settings, just the time setting. Thanks for any insight.
It may be that you have to change the time and wait till after the next backup runs for a backup to be scheduled at the new time. Ispconfig cron tasks work that way, it's possible backup scheduling does as well.
Jesse nailed it, and I was waiting for a 24 hour cycle to verify it. The db and web backups do transition to the next timing after they complete the current timing. However, mail is still on the original schedule. I'll let this run another day and report back with details if required. Thanks guys!