As mentioned, Jayco published weights are based on "unloaded" conditions, and are not even "unloaded" ship weights. To get an accurate unloaded ship weight, look for the yellow sticker on an outside wall....., it will have an accurate unloaded weight to start with.
One member on JOF purchased a 2014 28DSBH and the published UVW was 5,710lbs, but the actual Ship Weight (UVW) on the yellow sticker was 5,943lbs (includes weight of LP tanks when filled).
If you really want to know how much Payload Capacity you have available with your Escalade, take it to your local CAT scale under loaded conditions (full fuel, passengers, cargo, etc.) and weight it. Subtract the CAT scale weight from the specified GVWR noted on your driver's door. The remaining weight is what you have for a TT's "loaded" tongue weight and any other TV weight not accounted for at the CAT scale.
For a TT "loaded" tongue weight estimate for the 28DSBH, figure 13% to 15% of the estimated TT's "loaded" weight (cargo, fluids if you carry them, etc.).
2016 GM 2500HD 6.0L/4.10
2005 Jayco Eagle 278FBS
Reese HP Dual Cam
Putnam Class V