From my guy in HR who is a retired HR CSM, he states that you should have your ERB match your NCOERs. If you are forward, then the duty assignment on the ERB should match with the word "FWD"
I am not sure there is a standard, but when it looks right, it looks right and there won't be a lot of erroneous information on there. I think the biggest influence will be the NCOER and how the senior and rater feel about you as a leader. If those match, then you should be close.