I too am curious about the aforementioned.
Rating adjustment
I think it is for one of 2 reasons, or both:
a) your and/or your opponent's ratings changed between the time when you looked at the rating adj. estimation and the time when the game finished
b) your and/or your opponent's rating deviation constants (aka Glicko RD) changed between the time when you looked at the rating adj. estimation and the time when the game finished.
That said, this is based on my guess at how they give you a rating adj. estimate. In my opinion, they shouldn't give a rating adj. estimate (even with the "estimation" clause) to avoid confusion like you are experiencing.

Actuallay I looked at the rating adjustment estimation just before I resigned so it took me like 1-2 seconds so I had no time tofinish another game which would affect my deviation constant, and my opponent was offline at the time.
I was playing (and losing it) a game against someone with a rating 600 points higher than mine. When I checked the rating adjustment in the game window (the show rating adjustment button) it showed that I'll lose 2 points if I lose the game. But when I resigned, my rating dropped 10 points. It's not that i'm claiming the points back, I lost the game and if the formula implies that i should lose 10 points so be it. But I'd just like to understand what happened. And what cause of the difference between the actual points loss and the estimated one?