Well, I don't have C or E, I have D in the 285 70 R17. . .
I'm currently running the D load range. My second set waiting to go on are also D load range.
Could it be that the reason you are both running load range "D" is that the Goodyear Wrangler DuraTrac LT285/70R17 that you both claim to be running is available only in load range "D"?