In order to use timer based animation, you advance the frames yourself. I take a time stamp once per loop. It is the amount of time that has passed since the last loop. Let's say 20 ms have elapse.
I have an animation speed for each NPC. Let's lay I'm animating someone at 20 fps. So every second, 20 frames will have elapsed.
So, every millisecond (20/1000) frames will elapse. That's .02 frames every millisecond. So, you multiply the frames per millisecond by the timestamp, or in this case, 20*(20/1000). In this case, that's .4 frames. DBP allows you to advance frames by floating point numbers, and they accumulate as you go. This opens up a whole world of possibilities, including animation interpolation, blending, easily including backwards animations, and non-contiguous animation sequences.
Another thing, I never use the sync rate for timer control. I think that it's a sloppy and ineffective method for doing so.
Come see the WIP!