That’s not an issue. The player unit only advances when the ball actually traverses the “downhill” side of the trough. The outhole can kick as many times as it needs to.
I’m generally skeptical about doing this modification, though. My principal reason might surprise you. I’ve played Orbit and Outer Space (it’s 2-player version) many hundreds of times, and once in awhile, you can make a high-power shot through the spinner that continues through the gate and then continues UP the runway and around the top arch! The spinnner is still spinning furiously, you get the 3000, and it feels great because it’s so hard to do (YMMV). I think you really need to hold the ball in a kickout hole to run down the bonus.
One more thought, in case you still want to do this: consider a speed-count bonus, as implemented in Fast Draw and Quick Draw. You could count an entire double bonus (30K) in five cycles of the motor.