How do NCOERs work?

That is not the case. The only items that can't be added are events that occur during non-rated time or events that are captured on a DA-1059. Even then you could still add the performance as a benchmark of your skill. But I understand what they are saying. They are considering an achievement as an evaluation for a event. This is not doctrinally based. They should be able to use those events that you were awarded for. The best way to explain this would be asking how a board would know my performance if it wasn't on my NCOER? I have never seen a board in the Army that reads the bullets on an award as a means to evaluate a Soldier.

Your PSG needs to see your 1SG for some remedial training.

SSG(P) (Join to see)
Somewhat rhetorical question:

Have you received quarterly performance counselings? Quarterlies are a means for both the rated soldier and the the rater to discuss goals, accomplishments, and the way forward. NCOERs shouldn’t be a “surprise”. A lot of the common issues can be, and should be discussed prior to your actual annual.

I say all that as a nugget for you as you progress as an NCO. Not only for your own career, but for when you begin to rate others.

As for your immediate questions, CPT (Join to see) along with some of the others pretty much nailed it already.

Best of luck and I appreciate the honest question for a system a lot of us NCOs are a lot less familiar with than we’d like to admit; myself included.