[@Stern Algorithm][@MyCatGinger]
How I imagine James handled that biology class (which would have been during the previous semester just before summer break) is that for any given assignment James either did excellent work (95%-100%) or simply didn't turn anything in. Shou would certainly have noticed that James gamed the grades to finish the semester at just barely over 80% with only a minor amount of out-of-class time expended. Shizuka probably never interacted with James directly, but if she assisted in grading she may have noticed that he skipped a sizable portion of the assignments despite clearly knowing what he was doing.