Whirley everyone naturaly grades everyone and everything. Do you not say so and so is a good driver or the Indian restaurant is good/bad or indifferent.
The first thing an instructor wants to know on taking a student over is, is he/she any good. what student records do is provide that answer.
Grades 1 -10 never work because they allow too much ambiguity. you just need above average, average or needs more practice (in my opinion.)
Something I remember from the RAF which always made me laugh was
May well achieve the standard after considerable practice