Loaded (well, slightly overloaded) for camping, 1 battery, 2 20lb tanks on the tongue, 4 bikes under the bunk bed, no fresh water, minimal black tank and empty grey tank gave me a tongue weight of 700lbs (540 with WDH).
I don't know where they get that 390 lbs, but they must have moved everything heavy to the rear bumper, because mostly empty (most weight was behind the axles, except for propane and battery) I was 580lbs (440lbs with WDH)
My CAT scales visits here: https://www.jaycoowners.com/forums/f...sit-59158.html
As for the tongue weight scale, make sure to test it out after getting the trailer weighed properly to see how accurate it is. I tried out this one: https://www.princessauto.com/en/deta...le/A-p8686024e
(Princess Auto is like the Canadian Harbor Freight), and it was ~100lbs under the CAT scale weight. I ended up returning it, and if I were to get something else, it would be a better quality one (and would still test it)