[tentcamper]

the SAE standard assumes you are starting with:
· both a driver and passenger in the vehicle, each weighing 150 pounds;
· that tow vehicles also has 70 pounds of aftermarket hitch equipment

I also thought I read a few years ago that is also assumed wet curb weight with full fuel tanks. But I could not find that.

This could be as much difference as 600 lbs compared to some manufactures starting with a dry curb weight with no fuel, passengers or hitch.