My response to CB1 would be this- more people want to officiate high school basketball and since it is a more popular sport than soccer (at least in AD's eyes) then they are willing to put more money into the officials section of the basketball budget thus making the pay higher. That may or may not be the case, it is only a suggestion.
My only caution with ref evals would be NOT to fill them out in the heat of the moment. Many times playing, and now coaching, I seriously questioned a call, but when I saw the video, I saw that the ref made the right call whether by knowledge or luck. I think most teams at the high school level have one or two scorekeepers or managers for their team. Why not assign one of them or a suspended player or a hurt player to video? The coach could then make notes about questionable calls and then review the video after the game. This would not be a time consuming process b/c the coach could watch specific sections of a game or specific calls. This is an idea more to give a coach time to cool off and objectivly rate the quality of a referee. Yes, we all want to win but if a ref makes a call that is right and we lose b/c of it, he is still a good ref.