I've never seen a ball fall off either wireform on a WOz, and I've played like 20 of 'em. The fact that it's happening on both sides on yours is very surprising.
Where are they falling off? Some people have had trouble with the balls getting kicked out too fast by the crystal ball, but the returns from the castle and the lock should be quite slow. I suspect something's not right: either in setup or a factory error.
If they're falling off somewhere consistent, look for something that's causing the problem. If not, then I'm baffled