I'm absolutely baffled by this, and it's starting to get frustrating. I've got a guy that I run fireteam ops with, and he is beating me every time. I get a B+, he gets an A. I generally have more kills, so it's not that. It also doesn't seem to be tied to deaths or completing objectives. I had one match where a guy joined in at the end, had literally zero kills, and HE even beat my score. I really don't get it. It was amusing at first, but when I'm regularly getting lower-level gear than my friend does... Does anyone have the slightest idea how they determine this?