Agree with what Scott said. Easy way to look at it is listed dry trailer weights generally don't account for battery and propane. Do the math on the dry trailer weight at ~ 10 or 11 % and see if that is what is listed as the hitch weight.
But the glaring issue here is that listed hitch weight is always going to be lower than the actual wet/loaded hitch weight. And, a hitch weight at 10-11% of the loaded trailer weight could very well be marginal for a stable tow. The hitch weight may be needed to be increase to make that trailer tow stable without any sway event under normal towing conditions.