Champ Mastery Complaint (read desc.)

I'm trying to S Rank as Kha'Zix for my Mastery 7 tokens, and I just got out of a game where I go 4/1/2(died to red buff early as Teemo stole my krug and didnt realize until a moment later). Pretty much, a semi perfect game, not too much CS cuz jg, most wards with 7, 1/4 of kill participation, got both fire dragons, 2nd most gold, and I did do the least damage of anyone on my team, mainly from a slower start and teemo coordinating with Luc for kills, which lead to him being fed.

Though I get I did the least damage and didnt do much for my team, I still did relatively ok for a 20 min jg Kha game. In the end, this is just bull how I only got a B- with this score, as did Swain. IK that Riot scores games with averages, but I wish I knew what they were so I could know what I'm aiming for.

(Not only this, but I've done spectacular on other games recently with Kha, and I've only gotten as good as A+'s. I get the algorithm is based of participation and role, but I wish Riot could put the criteria out somewhere so I [and the community, really] can know what to aim for if we want S ranks.)

I just want my fav champ to hit 7