Can't downgrade from specific carrier update on Galaxy S6 Edge. Model SM-G925W8

I am looking to downgrade from firmware version G925W8VLU2AOG2 to G925W8VLU1AOCG. I have downloaded the firmware, and have loaded it up in ODIN through the AP slot, but when I attempt to complete the process I get the following error: imgur dot com slash vgCerPv

The ODIN screen on my phone says SW REV. CHECK FAIL. DEVICE: 2, BINARY: 1

I am trying to downgrade so I can root my phone (ping pong doesn't work with current firmware, and eventually flash a rom and run xposed (now that it works for the S6).
I'm running ODIN 3.10.7