Quoted from gdonovan:Again, no need if you set the credit targets low enough.
You will always earn more credits than you use starting a game till the max credit is hit.
which works great unless you want to have replays award extra balls, or don't want to hear the knocker go off for the replay at some obscenely low value, or you like having the replay levels as goals to reach, or several other reasons you may not want to do that.