This can happen for any number for reasons. First check to make sure your RBS is perfectly level. Next pinpoint any areas where the ball might be getting slowed down. Small bends to the metal is perfectly acceptable to correct any issues. If you think any larger bends are needed or if you feel like this is beyond your scope of knowledge, please don’t hesitate to send me an email. A picture of the problem area is a must, and a short video is even better.