Somebody mentioned options; I know we are not talking about vehicles in this class, but the point still stands.
The last year they where available a friend bought 2 LTL9000 Fords. Ordered the same axles, drivetrain and beds. Only difference, other than color was his driver wanted the extra padding, carpet, and seat covers so 1 had XL trim, and the other was XLT. I was in the scalehouse the first morning they brought the trucks to work. The fancy interior added over 1000 lbs of MT weight The cab of a 9000 is not much, if any, bigger than regular cab F150. If you want max payload/tow capacity you need base level interior.