If a 12,000 lb. trailer had 20 % pin weight (15 – 25% is the range), that would be 2400 lb. pin plus hitch, cargo in the bed, passengers, etc. That will cause serious droop on an F-250 and be right up against sticker rating for cargo capacity. To know real cargo capacity, find as similar a truck as possible on the dealer lot and look at the yellow sticker on the door jam. It is surprising how much less it will be. In my opinion Ford should be down rating the F-250 fifth wheel capacity based on a reasonable pin weight.