If SGP does not actually sync my mount then .....even though it has done the maths correctly (using your method) and puts the mount right on the position required.....will I not then have incorrect RA & Dec in my headers?
I may be reading your proposal wrong....but for me, having it sync the mount is an integral part of what I am trying to achieve. I start each night from the previous park position (which the mount "remembers"). From that position I do not do any alignment or model to reaffirm the mount position. When I want it to go to a target it slews to the location (never to the actual spot). At this stage I need the plate solve & sync to then determine what its needed to get it on the spot.
If at this point it does not sync the mount but just uses deltas, as you suggest to move the mount to the required spot, then I am pretty sure, as stated above, I'll be on the spot but with wrong positioning information in the mount (be it a very small error or otherwise). For me, I believe the sync is a necessity.
The above I think should illustrate where my concerns lie with your proposal......if I understand it correctly.