How am I not BPR 100?

I was just looking at my Reach stats and I noticed that for some reason I’m a BPR 83. Now at first this didn’t bother me but I’ve been looking at the people on my friends list, most of whom are much worse than me (not trying to brag, just being honest) and many of them are BPR 100s. Without exception my k/d is better than theirs and I can easily 1v1 them if I wanted to. Now I haven’t played Reach in months, but when I did I was one of the top players in the Anniversary Classic playlist (again, not trying to brag, just giving relevant info). Because of all this I’m wondering how in the hell I’m not at BPR 100, especially since when I look online there’s tons of people saying how easy it is. I’m a 50 in h3 & h4, so you would think this wouldn’t be an issue, but for some reason I’m not there even when my less-skilled friends are. Is there something I need to be doing other than trying to get a high k/d and win games? I intend to go for this soon, but I really thought I was done with Reach for good so this kind of annoys me. If you know what helps and what hurts please let me know so I can earn this as fast as possible. Thanks in advance.