That calculation can change. So, say the time is 07:30 and you calculate the next minute should be 07:31. But you just stepped off the plane and change your timezone so the time becomes 09:30... the timer won't trigger again until the next day at 07:31.
Or what if Windows updates your system clock a couple minutes? Same situation.
Like I said, these are both pretty rare conditions, but they exist in the real world. I wish they were conditions that mIRC handled internally.
