I really want to know why 8/8/41 is a B- or 2/2/32 is a B. When the next highest assists in the game is like 10. I just want to actually get a chest for all the games I'm playing this time... at least in URF it made sense, it was possible to get a lot of kills on anybody, but this is just ridiculous.
As always, you are not being graded against other champions. You are graded against players on the same champion in the same position. Keep in mind that Support is not usually a useful role to play any champion in most RGM's; try building in a carry fashion instead, because Supports are a product of the 5v5 SR meta.
It seems to me that too many deaths is detrimental to mastery scores.
But also keep in mind, you are graded against other players who play the same champion in the same role/location, so picking a popular champion in a popular place (annie/ mid) is going to grade you against a larger pool of other annie/mid games, rather than if you went somewhere less common, like annie/top (or perhaps annie/support).
When you game is complete, the system takes your relevant stats (like kills/deaths/assists, damage delt, wards, some other stuff - they never told us what it looks at specifically) and generates some score. Then it compares the score to the continuum of scores for that champion in that role/location, and assigns letter grades based on what percentile you fall into.
If you play in a combination that has a smaller pool, there is a higher chance you fall into a better percentile (statistics gets weird when dealing with small samples and the system is designed for pretty large samples)
It already is.
