I know I’ve seen on mine and another HS2 I worked on that longer screws sometimes are put on the plastics over the supercharger and the ball can hit them. This slows it down too. Check that and make sure its clean and waxed.
You could unplug all the magnets and plug in one and test one at a time with a ball.
Can you make a short video of a single ball in supercharger test mode? That should help share the issue.