Isn't that a function of the relative scores of the players at the beginning of the game, and so similar for all games (Finito or otherwise)? I don't think it has anything to do with the "game score" (so winning finito with 7/0 or winning finito with 2/0 won't make a difference to how many points you get, but a 1600 player beating a 1700 player will get more points than a 1600 player beating a 1200 player).