Yes, and now that you've attached the image of the mosaic setup I can tell you this is your problem. During the mosaic creation you can set the camera angle which rotates the image around. When you go to take the mosaic you need to set your camera at this angle so that the frames line up. It looks like it was pretty much exactly 90 degrees off. If you compare how you setup the mosaic in SGP:
With your captured frames: 
You can tell that the wizard has the frames setup to be in landscape and they were taken in "portrait". So it appears that your rotation was 90 degrees off.
And below is why:
This is actually 90/270 degrees rotated. 0/180 degree rotation would actually mean that your camera is in a "portrait" aspect relative to your dovetail since angle is measured relative to RA (which runs north and south). Also judging by the location of the vignetting below you had a LOT of overlap vertically but not much horizontally...which goes to further enforce that the camera angle was wrong (image rotated to match above framing):
It appears that these are all nicely centered where they should be but the angle is incorrect thus making the overlap >20% in one direction and <20% in the other direction. You can either redo the mosaic sequence creation with the actual sky angle of your camera or you can set your camera to the angle that you're setting in the mosaic creation, but those two need to match pretty closely to do a mosaic accurately with a minimum of lost pixels.
Hope that helps,
Jared
PS. I merged your two topics into one to keep things tidy.