Yeah, something is there...after all he is doing his favorite thing, contradicting Tom. Maybe it was irony not sarcasm..."It was the smart move. Tessio was always smarter." He says it with a kind of tone as if to say "I knew it would be Tessio." But back to the question...where was Tessio so smart? IN THE MOVIE NOT THE BOOK!
"Io sono stanco, sono imbigliato, and I wan't everyone here to know, there ain't gonna be no trouble from me..Don Corleone..Cicc' a port!"
