I've got all of my machines set up so they play as factory suggested, including the number of balls per game, as well as factory suggested scores to beat to win a 'free' game. There are times that it almost seems too easy to win, and I'll build up enough credits to play for hours, or for a few days. Then I go through streaks where it seems like I've never played before and every single ball goes down the middle or the sides without even having a chance to use the flippers.
Curious how this works for everyone else.