Oh! Alright, thank you. :) So if you go back and do something one hour in the past, then the loop closes an hour later, when the other version of yourself goes back for the same reasons you did, and now once again you are the only "you" at this moment in time. It's not A' that continues on with life leaving A'' off the hook, it is A'' who moves on while A' must go back. That makes much more sense.

Edit: This means it is always the oldest Harry that we see, right? The one with all the extra waiting around included in his age? Since all the other Harries are stuck in a six hour loop.