My LTC preceptor did the same thing to me. Gave me like a 2 out of 5 for knowing regulatory stuff for LTC when she hatdly even taught me any of that. How was I supposed to know about it. They don't teach that stuff in class and she didn't even quiz me to assess my knowledge anyways. She was my worst preceptor.
did you dispute the grade with your school? has anyone ever done this and succeeded?