I think that Tony Soprano knows this: what's the point of getting into a heated argument in front of everybody? Isn't it better to be perceived as weak, then to "spring" on your victim when the time's right.

Obviously Tony Soprano is no Michael Corleone, but Tony's no moron. I think he knows exactly how to play Phil, and coming off as The Sad Clown at the sit-down proves that.

Although...

He did show up without any protection to Phil's house "with hat in hand, on bended knee," and could have easily been whacked.

We know what Tony is capable of, we know he isn't a pussy. He came across as one, and was willing to walk into a potential House of Horrors with Little Carmine, so I don't know if Tony is working with all his cylinders. Tony would have zero reason to trust Little Carmine, who could indeed be working the fence. "Cooler heads prevailed," Phil shouted, and many people think this means that Tony would have been assassinated in that house. And Tony would have walked right into that ambush, too.

Little Carmine's loyality is with NY, if anybody, because of who his father was. Tony can't trust him. So who knows what's going on in Tony's head. Maybe he is a finnochio.