Nevermind, I found it, took some digging in these forums. I did note a strange stuttering effect when using the ang_add() function. It's odd, because I wrote a far more complex rotation system using quaternions that doesn't cause any stuttering at all. However, the stuttering seems to smooth out when I hit F11 and bring up the developer info text (the FPS/MEM/NET stuff). When I turn off the F11 info, after a while, the stuttering returns. This is very peculiar behavior.

Any thoughts?