Good points all around and I wont repeat them here. I would add that I thought FFC was having a little fun with the Woltz-Tom scenes.

Woltz was surrounded by yes men, and in those days he probably owned Johnny Fontaine's studio contract.
Everything about him would be in Tom's eyes (and Vito's), ridiculous. Showing off his wealth, saying what he paid for the horse, and what he planned to do with him, bragging about how he used marble that decorated the palace of a king for his ostentatious house, doing the fancy dinner with him at one end of the table and Tom at the other, talking business in front of servants, hiding the little girl upstairs, and most especialy wearing that stupid "My Cousin Vinnie" suit with piping combined to make him look ridiculous. Johnny did not have to make him look ridiculous, he already did, and to top it off, not only did he refuse the favor, he told Tom he was "no band leader."