I had a similar experience in undergrad school. I had 2 years of chemistry in high school andcould balance equations in my sleep. In a college chemistry course I got the correct answers on the first 2 tests, but they were scored incorrect because I did not use the method professor required. By the time I caught on and aced the remaining tests, it cost me a B rather than an A, resulting in a 3.499999 GPA at graduation and costing me a magnum cum laude, even though the requirements were a 3.5 GPA (2 significant digits) and the refusal of the college to use standard rounding rules. I graduated in 3 years with a double major in chemistry and biology, and was no dummy. I protested to no avail at the time but this cost my undergraduate school millions in alumni donations that I chose to give to my medical school instead.