What chassis is this on?
And, have you actually weighed it?
Or, are you working off of specifications?
Over the years, the Ford E350 (just as an example) has gone from a GVWR of about 11000 to the current model at 12500. You can see why. Still, we had a 1984 24-ft Holiday Rambler (built solidly which means heavy) on a 1983 E350. Weighed all four corners and they added up to just a hair below GVWR once we loaded our travel stuff.
FYI, I think you're right. The net capacity of many RV's is really thin, so many probably ARE running above max. And most likely loaded lopsided too. Which is why Michelin has an "RV" version of their tire load/pressure chart. It's set up with Corner Weights. The "Light Truck" version of the chart is set up with Axle weights. At least get Axle Weights if you don't already have them. $10 to use the CAT scale at any Travel Center (politically correct term for Truck Stop).
