The metal studs on the unit should hit the switches when it has all the bonus counted up or all counted down.
It won't count down if the switch is open and vise versa.
Check your switches.Make sure they close and contact.Count up manually and it should stop at the switch and at the open space.The opening is the max the wheel will turn.It should go down from there.
It's possible you have the studs on the wrong side of the switches