If I get constantly get an S grade even after numerous defeats.....
Isn't this a failure on Riot's part in balancing the game around equal skill level opponents.
Side Note: Title is confusing so I'll rephrase it.
"If I can get an S regardless if the condition is a wins or defeat, isn't matchmaking flawed when I get opponents that aren't at my skill level."
Support, you'll get an S almost every time because of the lack of people playing it.