For supply, you have understood right.
I don't think this is stated in the manual, but my understanding is that truck usage and wear, along with damage and destruction, is always based on traveled hexes and expended MP's, along like some hidden max travel mileage for trucks, and of course the weather, like for airgroups. So the more miles your trucks need to travel to get supplies to the units, the more trucks will be used. Therefore, if you can get below the min hexes/MP's for supplies delivery, it will be better for truck usage.
I also always try to use the organic trucks of the HQ's to the max and therefore limit the usage for the trucks in the pool. So that means that I try for HQ placement to have the minimum distance possible from HQ to railhead, and then when a few hexes have the same travel costs, I choose the hex that makes the distance to the units as uniform as possible.
That said, I have read at a few places that truck usage is rarely a problem in 1.12.03, and I don't know to what degree it is true. But it is definitely a big factor in 1.11.03
< Message edited by joelmar -- 3/10/2020 8:43:04 PM >
"The closer you get to the meaning, the sooner you'll know that you're dreamin'" -Dio