Writing assessments for a CS is no different from any other assessments except that unlike a military assessment which affects promotion and ultimately pay, for a CS your appraisal will affect whether they get an annual bonus.
I was in the other situation - my second RO was CS. I was not too bothered about promotion (PAS) and the end of career was near, but I never had my ACR on time to meet the promotion board (despite constant reminders) and the wording wasn't particularly military. I always wondered what would have happened had I redressed? (He was a good chap though, horribly overtasked, and I let it lie).
As to CS courses.... Working for the MOD meant that I had to do all the silly CS courses in addition to the military ones. The biggest bugbear was having to keep the CS computer system (PPPA?) up to date in addition to JPA - double the work (Leave, Courses, Post Information, Terms of Reference and of course keeping my ethic origin updated each year in case it changed).....