"I'm over on GCVWR of 15,250 by 250 pounds"
This - is the only relevant piece of information. The rest is noise.
I feel like you are taking this a bit personal and knowing you or the type of person you are has absolutely no bearing on the mechanical constraints of your RV. I never once said the MB sprinter brakes are under built, or the chassis etc, I was pretty factual. Heck I like the sprinters, I have 2 friends that own them. But, it's built a certain way and engineers arrive at capacity - Period. I think you are trying to justify why it's ok to be over. To each his own and I am sure you do just fine. But just because you feel that way does not make the facts and figures irrelevant.