There are two parts to a Navy FITREP: Performance traits (1-5, 1 being Below Standards, 2 Progressing, 3 Meets Standards, 4 above standards and 5 Greatly Exceeds standards) and Promotion Recommendation (Significant problems, Progressing, Promotable, Must Promote and Early Promote). Yes, a FITREP does list a Member Trait average versus the Summary Group Average, but the "CO/Promotion board only" score that I mentioned is the Commander's average for the command. That's what you don't ever see and that influences the board.
Like Bolter King said, you can only get so many EP, MP, P, etc. So you'll get guys backstabbing each other for that.