I think Im having the same issue as Pronus is having in the other thread.

I pick a point on the bed and set it to x0 y0 z0 with the G92 command.
Then set the z probe to that same spot and get the values of x-30 y7 z8.10
enter those in marlin as x30 y-7 z-8.10 and upload

Then enter g28 code....here the nozzle first goes to the back right of the bed, where the endstops and then moves to the point that I entered as the g92 location....except its shifted a bit. Then I manually put the nozzle back to the initial point on the bed and hit m114 and I get x106.60 y133.30 z-4.30