Level 6/7 Mastery Ranks BROKEN?
I just went 12/0/6 with 74 cs on Lee Sin Jungle, the game was a victory by enemy team forfeiting. At the match results I had gotten an S- and since I'm level 6 and need level 7 this got me tilted. I mean how can 12/0/6 give me an S-. According to what they said about the mastery rankings, S means you were just at the average for the champ and role played. How is 12/0 not even close to average. Like seriously I've gotten 5 S- and I just cant get this level 7 Lee Sin and its starting to tilt me..
This is the screenshot of the match history:
https://gyazo.com/e34238aad5bb2296df0991e2239449d3
Please someone explain to me why this is S-, and also explain how to get S or S+ i've been playing Lee Sin way too much and I'm starting to dislike him because I just can never get an S or S+ and I'm doing pretty good each game...