On second thought, maybe I won't go for 1000 on Mass Effect 1. I just beat it again last night. Anyway, at the beginning, as soon as I was able, I went and got Wrex and Garrus and used them for literally the rest of the entire game. The achievement for using Garrus unlocked, but the Wrex one didn't. What a bunch of bullshit. And I'm not playing a game all over again for 20 points, I tell you that right now.
Maybe I'll load a save game and see if it works a second time or something. But for now, I'm pretty mad about it.