"The tires not the door sticker"
I can only speak for myself, but when I reference the "door sticker," I'm talking about the "Tire and Loading Information" sticker in the door, which is the one that spells out the actual payload capacity of passengers plus cargo.
In other words, the door sticker that matters is the same thing as "the tires."
That said, if I wanted to make a case for a higher cargo capacity, I'd point to the fact that the sum of the axle weight ratings is higher than the GVWR (likely to account for uneven loading, or perhaps for braking performance).
