If they come out average because their exceptionalities don't show on tests, and they don't have any outrageous behaviors, it's actually pretty easy for a school to miss them.

Seablue, seems to me your job is now to keep explaining and educating. Keep your evidence handy, help them see what you see, treat the school team as "on your side," but keep showing them and documenting issues that arise. It can take a long, long while. But sometimes you really can get it done.