Maximum Loaded Trailer Weight assumes a towing vehicle with any mandatory options, no cargo, tongue load of 10-15% (conventional trailer) or king pin weight of 15-25% (5th-wheel trailer) and driver
only (150 pounds).
Weight of additional options, passengers, cargo and hitch must be deducted from this weight. Also check Required and Recommended Equipment.
Basically Ford HAS deducted the driver weight of 150 lbs from the cargo weight since it has already been deducted from the GCWR..
What you're reading in the above is the TOW RATING, says nothing about payload. It just says that the max tow rating is calculated with a base truck, with no cargo or passengers other than 150lbs for the driver. The tow rating decreases pound for pound with weight added to the truck.
What it does say about payload is;
"Make sure vehicle payload (reduced by option weight) will accommodate trailer tongue load weight and
weight of passengers and cargo added to towing vehicle."
That's ALL passengers, driver too.