In the absence of other info., the 80% thing is a quick ballpark rule of thumb for the max. weight of trailer you can pull. It is 80% of the vehicle's rated towing capacity in your case, the 2800 lb figure. But then there is your GVWR, GCWR, axle ratings, payload ratings, etc. to work with and ultimately, it's good to take your TV and trailer to a scale. Not sure if SUVs have axle ratings, etc. though?
Bought our first TT using the 80% rule of thumb for our old V6 F150 with a max. TC of 5500 lbs. That was before we knew anything about payloads, GVWRs, axle ratings and all that. The TT had a UVW of 3800 but ended up at 5000 lbs all loaded up so we were under the max. TC. But, the truck struggled on steeper hills and a few times we ended up crawling at 30-35 mph flat out on the freeway along with fully loaded semis off to the right.... Also, not fun with head-on buffeting winds trying to maintain an even speed.
Gil & Deb & Dougal the Springer Spaniel
2014 KZ Spree 262RKS & Ford F250 supercab V10 4x4 LB