Can't increase coaching staff?

This happened pre and post winter patch.

There are 10 types of training to assigned coaches against - but I can't get higher than 7 coaches (which includes the assistant manager). That means I have 2 types of training that won't be as high as they should be …if that makes sense?

No matter how often I ask, and what speech bubbles I select, nothing works. 

This is as Celtic, so no idea if other teams have this issue?