why not just shutdown?
instead of automatically rebooting the machine, why not schedule it to shut the machine down?
If you don't have anybody working past 12am until 6am, that's 6 hours of electricity...
fwiw, I recommend that people shut down their machines once a week... typically on weekends, and start fresh on Monday morning (or Sunday, depending on when the start of their week is...)
This scheduler could go ahead and shut their machine down over the weekend for them, if they forgot to do it themselves... pretty cool feature!