Quoted from lynnpin:For what it's worth, I just played a game until I "Locked" a ball, then I added an additional ball so that there would be 3 balls in the trough, 3 in the Gumball, and 1 in Lock. The machine did as before, dispensing 2 balls into the Shooter Lane and leaving the "extra" ball in the trough ready for dispensing. Still a mystery as to why 2 balls are dispensed only when the Lock is made.
There's your problem - TZ is a _six_ game ball, and 3+3+1=7.