I'd be leary of that. My last truck had an APU and I nearly got nailed in Ca. for being 80,012. The only reason I didn't is because the CHP officer said I looked young and dumb.
No, that was not a federal mandate. Every state can give it the thumbs up or down. http://www.ooida.com/Education&BusinessTools/Trucking_Info/Vehicle_weight_exemptions_for_APUs.shtml
Thats what I thought. You can't count on anything being the same from one state to another. They all have their own ideas and half the time they don't mesh with the sates around them.
12 lbs? no DOT scale anywhere in the us goes by 1,2,5,or 10 lb increments; they all go by 20 lb increments. come up with a better 1