I don't get how the grades work...
Can someone explain it to me? Like I've had games where I've had 20 kills and close to that in assists and only a few deaths, but gotten an A+, then others where I feel I played "ok" and got an S. My last game that got me promoted to Gold I got a B+ after going 10-0-9, getting every dragon and baron. Is it just arbitrary or what?