Well, to be honest, I can understand why they would not let me take the test in my rig: technically, if I load up to max GVWR for each vehicle, I would be exceeding the combined rating.
If they only police via GVWR, as far as they know I could be showing up at the test already exceeding the rated capacity of my vehicle combo, making the whole point of ensuring I am operating safely moot.
Further, should I get in an accident, even with the Class A license, I'd be exposed to liability since research could show that GCWR was being exceeded (they're not going to weigh the debris after an accident to calculate actual weight, they'll just look at stickers).
What I am trying to accomplish here is a step toward being legal, perhaps with a new truck in the future to make it official.
A step towards being legal has to be better than nothing. Holding that Class A license could be the difference between being or not being impounded should I ever be pulled over. I doubt the officer would look into my owner's manual at the time, he would just look at my stickers and my license.