I owned a 2011 F250 6.2 CCSB with 3.73 axle and was only getting around 11.2 mpg, 7.8 when towing 7500lb trailer.
Had the hard 2-3 shift while accelerating down an on ramp while towing my trailer and thought I lost the rear end.
Bought last May & traded this July. Not sure if you all have good ones or I had a bad one but I expected a little better mileage.
2013 Ford F350 Lariat 4X4 SRW CCSB 6.7 Powerstroke