Good call on the Yeti. We have a 2wd of 2014 vintage that sits with the van very slightly nose up.
We had a similar problem to you with a VW Touran [same floor pan] and Westfalia bar some years ago. I looked into it in some details and it's all in the small print. The tow ball height is calculated on a fully loaded car, so you would have to get possibly more than 600kg in to take a true measurement. We have found ballasting the car on the way out with as much as we can fit in and with wine on our return from France has solved the problem.
The following show the car fully loaded for the start of our French trip last year, ie in the car we had 2 adults, fridge, freezer, big awning, 2 x tables, satelite dish and tv, heavy food boxes, shoes, electric cables, wheel lock and odd clothes.
a - August 2017 - 800.jpg - Bild entfernt (keine Rechte)b - August 2017-800.jpg - Bild entfernt (keine Rechte)
Colin