In every 2D/3D package I've seen, you have the capacity change two basic motion blur parameters:

Shutter angle, as you described, will affect how long your virtual shutter is open to render.
Shutter phase (often has different names), the ability to shift the timing of the shutter left or right on the timeline.

What I meant to say is setting the shutter angle to the original footage is important, and if the image renders shifty with motion blur, the problem for me has often been a simple matter of shutter phase adjustments, which without seeing the OPs video issue, seems a likely solution.