Mastery Grading System

I have noticed that as a jungle main, I do not seem to find myself getting many S ranks despite having a great K/D/A and participating in a lot of objectives. I recently watch a video posted by YouTuber 'Gbay99' where he stated that CS might be a very very important aspect of achieving an S rank. I feel that if someone is playing a role that does not get above average CS every game (Jungler, Support) then the importance of CS going into the grade should be lowered. If you are having similar problems/complaints with the grading system or know of why this is constantly happening, please reply. A few screenshots: One, Two