Scott - I just wanted to let you know that I feel your pain.
I received a report from an umpire last week that a JV coach (NFHS Rules) presented a lineup at the plate meeting with an EP. When he was informed that HS rules do not allow for an EP, only the DP/FLEX, he (the coach) said that he never did understand that "DP/FLEX thing" and preferred to use the EP, and he had been doing it all season (about 10 games so far)!
While I have my doubts about the validity of his claim, it certainly would not surprise me if he had been allowed to use the EP previously.
So now a memo goes out to all of our HS umpires......