It sounds like a bug. I don't think moveing should get hours above 240. So if you have more than 204 hours when you move, you don't get the full 36 for moving. And if you have more than 240, you get none. At least I'm pretty sure that's the way it's supposed to work.
303 seems to be a bug. You can get more than 240 hours if another game triggers a vacation day. In that case 24 hours are added to every game making it 264 max.
I think there are some other bugs in the timing algorithm as well. I am pretty sure some of my opponents where awarded several hours when they came back after a vacation day. In some cases their game where down to let's say 50 hours. Adding a vacation day made it 74, but when they came back to make a move they suddenly where back to 240 hours.
I have so far not been able to spot a pattern for this behaviour. It is rather rare and not the usual behaviour after returning from vacation.
Not the way it's supposed to work. If you have more than 240 hours and you move, you get no extra hours. If you get another vacation day you do, but that shouldn't happen more than once per 24 hours. So it should be impossible to exceed 264 hours.
You seem to be assuming that the player who is using up vacation days is on turn in every game, which need not be the case. 303 hours is easily possible - it will happen if your vacation days are being triggered by one game, but in some other game it's your opponent's turn and he doesn't move for several days. Since your clock isn't counting down in the second game, it gains 24 hours every day. I've seen clocks go above 500 hours this way.
Are you sure it would be reset? I would think it would just wind down to 240 hours, with the player getting no extra time pre move until his clock (calendar?) falls below the 240 mark.
Here it goes: Just like mentioned it can easily go up above 300 hours but as you come back from vacation and start moving again it will be reset on 240 hours. If you have one game with let's say 280 hours left and you do not make any moves in this game then the time will not reset to 240 hours, only when you start moving in that particular game.
Here it goes: Just like mentioned it can easily go up above 300 hours but as you come back from vacation and start moving again it will be reset on 240 hours. If you have one game with let's say 280 hours left and you do not make any moves in this game then the time will not reset to 240 hours, only when you start moving in that particular game.