Riot, why no S for my awesome Taric game?

Mastery 7 Taric here.

You need a K/D/A similar to that at about 20 minutes as opposed to 34. Your total kill participation needs to be higher too.

Orianna was part of 29/45 of your team's kills. You were part of 23/25. 64% participation compared to 51% participation is the clincher here. You'll rarely get S- and above with a kill participation below 60%.

That happens.

I've dropped to the math and apparently as Bard I HAVE to do better than 4/4/18

5 Deaths? A+

3 Deaths? S- - +

Maybe not enough assists.

That and your KP wasn't up to snuff.

This probably isn't the case due to your Ruby Sightstone, but were you slacking with warding?

You probably needed to get a pentakill. I once saw a 5/0/40 only get an A rank

The grading is so wonky. I understand it depends on the champion, but come on ... I've had at least half a dozen amazing games these past couple of days and I get As. This one below just happened. I was like "that's for sure an S ... finally". But, nope. A+ ... like really

https://gyazo.com/2654bcbf4dde6f473b0bf41b504d153e

I got an A+ going 10/1/28 with support sona and I was placing wards whenever I had charges. 0/0/27 Janna was a B+ rank 4/2/36 Nami was also only an A

I understand there's a lot of factors going into the grading but come on, seriously?

And in response to the kill participation part, I've had several more games where I've literally only missed 1-5 kills and still no S ranks