ccc (cargo carrying capacity), gvw (gross vehicle weight) and gcvw (gross combined vehicle weight) are 3 different things, they are related. ccc is all the additional weight the vehicle can carry on its chassis. The weight of the vehicle, passengers and cargo should not exceed the gvw. gcvw is the combined weight of vehicle and trailer/toad. If trailer/toad puts tongue weight on tow vehicle, that weight has to be accounted for in the ccc on tow vehicle. You can flat tow with no tongue weight and carry full ccc in tow vehicle. You can carry some extra weight in toad/trailer, if toad/trailer weighs less than hitch rating, and you don't exceed the gcvw or the gvw of the toad/trailer.
If you rig and toad come in at or under gcvw, but one or the other is heavy, just move stuff around.
This is what most of the discussions about "how much water do you travel with" or "groceries from home vs on the road" etc... are about, in the end.
The library and glossary are full of info, particularly the stuff ya didn't know ya didn't know.
Bill