Riot fix your system,honestly.

cs and your kd aint amazing it only counts assists for supports. Plus your turret inhib cound mighta been bad but i cant see that. And it judges you based off every other yas player so you werent in the s tier of yas players. Also in stomps you need to do significantly better because the game knows your team was significantly better. Your team had almost 3 times as many kills. Honestly your lvl 7 you should already no what it takes to get an s on yas considering you have at the minimum 5.