you gotta keep the work miles the same... AKA 40 miles
gotta make it fair
did your work sudden become 20 mile less??
a truck or suv is not made for long commuting.
They are best designed for specific purposes.
So If my truck eats up 20 miles to a gallon, I'll use it for towing or home depot runs. Are you going to use your 40miles a gallon honda civic to tow a boat?