I am downloading the manual now, but I do know for my machine it took 8 balls. Also, these are not standard pinball balls, they are larger. I believe these are 1 1/8" dia balls while standard pinball balls are 1 1/16".
Thank you. I just checked the manual and see the same thing, it's not obvious though, I see the 5+3 extra = 8. I kept looking over that somehow. Thanks!!