I'd like a little clarification on what your calling Global origin. I think I have a pretty good handle on the whole design plane/cube but it's not alway clear when you say 0,0,0 and global origin which I always considered to be Global Offset.
As I understand it if I place a line starting at the center of the design cube. The coordinates stored for this point is stored in uors and would be 0,0,0. If in move the GO so this point reads out 1000,0,0 then MS will simply add (to the coordinate readout) 1000 Master units to the actual X coordinates.
When were talking about SWA you (Brien B) are saying it basing 0,0,0 around the GO of the file and not 0,0,0 uors? Therefore if I move the GO the SWA coordinates actually change whereas regular elements keep the same coordinates uor values.