Hi!
Oh great, one of those cases in which I just can't see the problems you are talking about.
It's doable (with enough time invested, I cannot foresee any huge problems)
Actually, it doesn't need much time investment. In fact, I have a pseudo-coded class to handle things with time instead of AP ready to go, I'll send you a PM.
This would make a lot of thing easier and harder at the same time
The only thing that is getting more difficult is balance - but at the same time it is getting a lot better because of the flexibility.
Main argument against are backgrounds... which any player would expect to reflect time of day.
And who said that the player is working during the night?
8 to 18 o'clock are very usual working times, can't see a problem here.
Need to take a look at the code when time permits. It's fairly difficult to tell what's best and what's possible, maybe we don't actually fraction the APs, some actions will take 1, some 0.5 and some 0.33. We wouldn't subtract APs directly, 1/3 would mean 2 actions for free and -1 AP on third or something like that.
This actually brings up more problems than a time based approach (and in the long term it will be more work because it's more difficult to maintain).
Also, it is a lot less intuitive because your actions don't reflect AP changes immediately.
Have fun!