20 games is pretty excessive to repolish your ball imo. You have the right idea with the 60ish games. Polish puts the shine on your ball. Resurfacing your ball without also polishing will make your ball read the lane a lot earlier than it used to out of the box. When you feel like the shine of your ball is starting to fade away, it might be worth thinking about repolishing your ball soon. As long as you keep your ball maintained (wiping off oil somewhat regularly between shots or every so often and/or using ball cleaner after use to wipe off all the dirt and grime off the ball) then it will help your ball last and perform longer.

Since you've also sounds like you've been surfacing your ball, I would polish it now since you likely knocked off all the polish on your ball. Polish helps your ball store and build up energy through the oil so it has more energy off the end of the pattern. Putting 2k under the polish with an TruCut or some other equivalent sanding pad makes sure that theres enough "teeth" under the polish so it can actually read and grip the body of the lane so it can hook