God I hate Steam's new interface, never notice the notifications now. This issue was sorted, long story short the connection between two things got broken which disabled the extra levels and I didn't notice.

uh any update on this

Heads up: There is a mod on my own personal server (did my testing in singleplayer, doh) that is overwriting the file that my mod edits that controls the levelling curve for NPCs, I'm currently trying to track it down and work out whether I can fix it or it's a hard incompatibility