It used to be that when an App was updated it would go to the top of the date list, this doesn't happen anymore, which is a real pain if you want to know if an update is available. There seems to be no rationalle to when the Apps get updated or new ones arrive, I assume they get on there as soon as the creator submits them and since coders have been known to keep very odd hours (I know I have when coding) this could be anytime.