Yep. This. I have a Limited with about the same payload as the OP. Rambox, MFT, eTorque...they all add up. The only way to know for sure where you are at with your payload capacity is to scale your full rig. CAT scales are your friend...the app is easy to use, and while it costs a few bucks it is better than doing all kinds of mathematical gymnastics to try to guesstimate your numbers.
I scaled my truck without trailer, with empty trailer, and then with the trailer loaded with my heaviest towing item. That lets you know how much hitch weight the empty trailer puts on your hitch, and then when it is loaded you can figure how much of the total load weight is on your hitch vs the trailer axles. And you can see how much difference the load positioning makes. Too far forward and you can overload your hitch weight quickly.