Was their the whole time thinking "Oh Hell YES! going to get a mastery 7 token for taric finally." Got to end of game screen got a chest was like ok yeah now gimme my token just for their to be no more pop-ups looked at my score I got a MOTHER FREAKING A not an A+ just an A, like what is up with the scaling system that 5/0/31 isn't worth an S, and I don't think CS should play a huge point at all in getting graded as a support.
You had 13cs and 9 wards.
Supports should generally have at least 40cs and have placed a high amount of wards (I usually aim for at least 20+ ; I do have 7 supports at rank 7).
You also didn't have a completed support item nor and upgraded triket.
You're missing out on key factors that supports need to utilize. 
or 
and any of the three: 
once the quests complete.
These items dramatically increase your vision score and will most likely influence your ability to get an S rank.
Warding using 
isn't enough. You really need to use the red trinkets stated before to help clear out any vision when it comes to taking objectives and preparing ganks.
Additionally, you'll also want to consider buying a few 
from time to time. Since vision score is determined by how many enemy players are scouted out by the ward during their uptime. So the longer the wards last AS WELL AS the more enemies they scout out, the higher your vision score becomes and should therefore increase your likelihood of getting an S rank.
S ranks are relatively tough to obtain for reason. Perfect KDAs aren't all that determine a players in game aptititude.
My last match as taric support we lost that match, but I still walk away with a "S"I went 5-0-0. Maybe lack of map awareness?
