I think you have the correct numbers assuming you didn't have a your weight distribution hitch tensioned. That would throw your numbers off.
On the trailer max gross weight spec, the DOT requires FR to state that as no higher than the axle max weight rating (3500 lbs) plus the lowest listed tongue weight (268 lbs). So, the fact that you have a higher tongue weight helps take that extra load off the trailer axle. Not that I'm saying its Ok from a legal perspective, just that its not as bad as it sounds from the technical point of view.
You are right at the limit for that trailer axle. If that is before tensioning the wdh then you'll be well over 3500 lbs after that. I have the same trailer and the same issue, and I'd guess most folks with 179's/180's that boondock like we do aren't that different.
I would advise upgrading tires and possibly wheels if you haven't already. I also reinforced my axle, you can look at my thread on that topic. The tires are the biggest concern since they can have a catastrophic blowout failure. There isn't any evidence of axles failing dramatically, they just seem to lose their camber over time.
You could also possibly move some of your gear into your tow vehicle if you have extra load capacity there.