Guys, thank you for the replies. Much appreciated.
Scale the Media was never checked. Zoom to Fit was just used as a convenience in measuring (never use it otherwise). On or Off, no difference with respect to border differences, of course the photo was a different size.
There is one thing I finally did:
For the Page Setup, I am using Landscape (mistyped above) orientation, so my neck doesn't get stiff looking at a Landscape photo. This is where the borders are off by .15 on each side. I decided to set the page up in Portrait, same as the paper is positioned in the printer. I get a significant improvement in print layout. The difference is only .07in versus .15in. With Mirage print the border was .03 diff.
The feedback on the wide format printers doing even borders at least give me some peace of mind, it's not me. It bugs me but I guess I have to live with it. After all, only I will know under that mat, the border is off!
Again, many thanks to everyone who has taken time to reply.
-tony