I'm fairly new myself, but I can tell you what I usually do. When I get the reel out of the cab, I work it manually to see how well it rotates and where it may be getting hung up. Just keep clicking the plunger using the nub that sticks out. They typically seem to hang up while moving from 9 back to zero....where the switches are getting the biggest workout. It's interesting that yours is having trouble with a specific amount of point.
If it's getting stuck anywhere, you need to break it down and clean it up really well. A lot of times I find old grease that has solidified over time, making the mechanisms move slower than they should....or just all the coil dust that blows around. In any case, when cleaned up and adjusted properly, the score reel should click along easily and have a nice snap in between numbers. That way you can rule out the mechanical aspect of the reel as the issue if you're still having problems after that.