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.

Yep, I agree.

It's definitely getting the five pulses you would expect, and it seems to be pulling in fine...so the solenoid seems OK. It's just the plunger is not coming back all the way like it should (at times). Since you said it moves fine when you work it manually, I'm assuming the rod moves easily thru the sleeve? If so...and you can rule out a mechanical issue...maybe the switch sending the pulse needs to be checked for it's gap. Maybe it's not always opening and allowing the plunger to return properly.

Just thinking out loud.