I've never paid attention, just assumed that after the clock hit 2:59:59, the next tick would be 2:00:00, but that's not the way it happened.
My clock stopped at 1:59:59, and left me without a visible working clock for an hour, but curiously, a test folder created at 2:40 showed an incorrect creation time of 1:40, i.e., the clock had already been set back an hour behind the scenes.
Artie, it looks to me like you have WWWWwwwwaaaayyyy too much free time on your hands.....