I remember this grading system from when I took Chemistry in High School. The system has a major flaw. If you start with a high score, but do not advance very far, it does not count how much you know in relation to the rest of the class.
The teacher gave a college prep exam before and after the course. As a first year student, my starting score was higher than the final score of any of his second year students. (Always learn a subject before you take a class in it.) Blew his grading method out the window. (As did my experiments in his class.)
