Blu-ray / DVD masters? vs. Adobe Encore CS6?

Just curious ....

I have to author a number of films. They were shot in HD and mastered to ProRes 422 using FCPX. It seems like the only Blu-ray authoring app out there now is still Adobe Encore CS6, since the death of DVD Pro. Barring some older and very expensive PC apps.

I've set up the menus, links etc. using Adobe Encore CS6, using the ProRes master on the timeline. Now Encore is going to create the disc image file.

And I'm suddenly wondering if I might get a cleaner, better quality, image if I create my DVD and Blu-ray master files using FCPX or Compressor, and then import THEM into Encore to make up the menu, links, etc., and create the disc image from that? Will Encore re-encode the MPEG4 / BDMV files to make the disc image? Or will they just use the FCPX or Compressor created MPEG4 / BDMV files as is?

And will I get a better end result?

Or is Encore doing a fair job of converting the ProRes to the DVD / Blu-ray formats?

All ears,

Ben