It depends how you run the test....do you standardize powder charge or MV? Now, to TRULY say "flattest-shooting", I think you need to standardize MV. However, from a practical standpoint, I see the value in choosing 100gr charge as, IMHO, that's about where most loads in most guns begin to experience problems with accuracy.
Now, at 100gr charge, I agree the 200gr SW would be around 4-6th on the list. However, in my experience and that of many people I know, it is tough if not impossible to push any PR bullets over 1800-2000 fps depending on the gun without losing accuracy (likely due to the softness of the lead). I can push the 200gr SW to 2100fps with 110gr charge; so if I tested each bullet at the highest velocity that shot accurately out of any of my MLs (say 1.5" 100yd group) and compared them on that basis, the 200gr SW would actually win.
PR will debate that their bullets cannot be shot faster (they certainly doubted my claims on the phone, but they haven't shot my guns and are hardly impartial), but that's been my experience.