SubD to Nurbs - slow (several bodies)

I have several SubD bodies that I want to convert to Nurbs in parallel.
They are not connected bodies, each one is an independent body.

I use the tool Convert to Nurbs.

The PC then processes the job. I notice that only one core is being used by my CPU.
Is that correct, that Rhino processes each body one after the other with only one core?
Can’t Rhino use multiple cores for the conversion. Ideally, each body has its own core for the conversion from SubD to Nurbs.