This is an interesting question - and open to many different interpretations. In my opinion the statement "let me ask you something, and I want you to be real honest,
do you think I need to lose some weight?" - carries several layers of meaning:
- respect
- gotcha
- you know where to find me, etc.....
- but mostly - I just hustled a hustler.... how did I do?
Early in the movie, Fast Eddie tells Vince - Kid - keep the shirt - it's a nice touch. He also says something to the effect - you are an incredible flake - people will be lining up to play you.
Amos lost all prestense when Eddie asked him the second time " Are you a hustler Amos"? Amos fumbled a bit - then decided to drop the pretense. He gets clear eyed and asks "why -do you want to quit".
Amos knew the act was over. Eddie knew Amos was a hustler and he had been called on the carpet for the end game. Amos recongnized Eddie's kind if not actual persona, a strong game, a wad of cash, a Balabushka. Amos basically told Eddie - yea - you are a hustler - I am a hustler - want it all? ---- Amos made a decision to go for the kill.
Eddie bit the hook ---- and he bit hard.
The statement at the end of the match was basically an honest question - he was saying "Eddie - you knew and you still bit". How was my performance old man?
Just my humble opinion.