*NVM I solved this by calling “scene.frame_set(frame_number)” instead of “sce.frame_current”, which seems to only set the frame after the script is done executing.
In Blender 2.49 I had a script that looped through all the Pose.bones.values (which are PoseBones). And all I had to do was loop through every animation frame, set the renderer scene current frame, and call PoseBone.poseMatrix which gave me the bone matrix for whichever frame I was on.
In 2.77 right now I’m porting this script and I’ve called PoseBone.Matrix_channel, which I though might do the same. I’ve tried several other things. It seems to just keep giving me the same matrix over and over for all 900 animation frames, no matter which matrix I export.