In addition to the cost of running your truck per mile, the cost of sitting per day must also be considered. What's better, one or two runs a week that leave you sitting for half the time but pay $2.00 a mile, or several runs a week that pay $1.25 per mile but keep you moving most of the time?
If you are in a fleet owner's truck, the goal is to maximize your gross income, regardless of how many miles you drive. Run, don't sit, because you could care less how much it costs to run your truck. That's the fleet owner's problem, and even more so if your fleet owner pays for fuel. You get a percentage of the gross, so maximize your gross.
If you own the truck, the story is different. And the story will differ further among owners because their business assumptions and needs vary.