I have a 2012 F350 Lariat FX4 pulling a 44RLS Work and Play TH and I gave up on trying to figure mine. Too many varibles to contend with hills, wind, traffic and so on,Mine will go all the way from Full to empty without stopping, however my bladder will not any more so when I stop I top off and go again. If you sit around and figure up how much it is costing to have a good time, then chances are you are not going to have one. BTW, it does average 10-11 on the highway @ 70mph.