I'm new at working on EMs and I'm having virtually the same problem on a couple machines I'm currently working on. The game does not end after the fifth ball.
On my Gottlieb Spin A Card, the ball count advances through 5 balls but then the game doesn't end. It keeps on going.
On my Williams Lucky Strike, the ball count (and counter) sometimes stops at 5 but most times it advances to 6 or 7. The reel that keeps track of ball count also advances to the accurate number of balls whether it's 5, 6 or 7.
Ideas anyone?