I think that Mike answered right away because the "offer" mirrors the $1,000.00 offer that Vito made to the bandleader, which story Michael told Kay at Connie's wedding, just before saying, "That's my family, Kay. It's not me."
He actually "one-up's" his old man. Vito came back the
next day WITH Luca.
Michael takes a different approach. Dont leave Senator I will break it down for you RIGHT NOW.
