I have an upstream and downstream WSUS server. When I set the upstream for say 2 am, it immediately changes to something between 2 and 2:30. I get that, it says the schronization will start up to 30 minutes after your schedule.
On my downstream server, I set the sync for 3am. I checked this morning and it ran at 6am. I then looked at the schedule for the downstream server and it is set to 6am. Why did it jump 3 hours?