Being a teacher has a lot of power. The power of imparting knowledge and the power to give grades. Undoubtedly, the part about imparting knowledge is the most important part of the role of a teacher. But as a student, who is only hungry for a good grade, it is hard to convince (especially in Singapore or Shanghai and especially near the final exams) that what you learn from a class is far more important than what grade you get.

Undoubtedly, once you become one with the professor in knowledge, the grade you get is immaterial. And with enough practising and learning, a student who can reach the level of his/her professor, never have worry about his/her grade. This, of course, is the highest kind of learning seldom seen or realized in contemporary schools but highly sought after in doctoral level of the best schools (and certainly in Zen schools).

$\int_C {\bf F} \cdot d{\bf r} = \int\int_R N_x - M_y \, dA$

That aside, grading hybrid and grading schemes are usually undemocratic. The student (even students in a class) have little or no say in how the final grade is decided.

In the late eighties in NUS, my grades for the exam (there was only one exam for each subject every year) was totally mysterious. One never saw his/her final exam paper back and some who requested to be re-graded, had to write letter(s) of appeal and after many bureaucratic steps, still would not be able to see it, but got an “answer” from some reviewers assigned by the university that the grade was correct or not. I never had to request that but I know students who do, and none of them won in the appeal and had to re-take their exams anyway.