After Game rankings are a fucking joke.
I have been playing Jarvan forever. I don't need you to tell me when I have played well and when I have not.
However, I have seen it consistently enough now, where I play a very cool measured controlled jungle game, warding for my allies, ganking to get summoners and objectives before kills and all the like and generally being a very good control jungler with a score of maybe 2-3-12... I get a b-. Yet when I build duskblade and hydra and just go completely ham on everything with a kda of 9-9-28 only THEN do I get the S ranking.
Now, the thing is Riot, I know which of those is good and wins more games, but you DON'T seem to. Because your scores reflect the opposite.
I don't know what fucking algorithms you are using to calculate this bullshit... And I don't think YOU do either.