Uh, no, this was a war-time example. So were my notes about "incoming Units". When we were relieved in Afghanistan, our work was pretty much thrown out, despite the fact that we'd had the most successful deployment (in terms of native opinion improvements, processes improved, etc.) of that theater in years (for our AOR anyway).
While I appreciate the logic of your argument in theory, I assure you, there is no such thing as a "magic efficiency button", which any actual soldier will tell you (or rant to you about) for hours ;)
It's interesting to read the thoughts from people on HN, RE the military, because they are almost universally preposterous.
I wouldn't trust my life to a general who hadn't also successfully run a company full of people who didn't care what he thought and quit when he did something stupid. You may be an experienced military X, but you'd probably be a better X if you also knew how to do X as a civilian. In fact, you'd better be ready to do X as a civilian when your service is terminated, however that may happen.
If you ran everything at full efficiency you would need far fewer people - but then in a war there would not be enough people. So you do everything inefficiently so the people (and resources) are there when you need them, and in a war you press the magic efficiency button.
Take your examples:
The loading/unloading was a form of exercise.
Sending the full truck back was a way to keep the truck drivers busy, and also of making sure the trucks are used.
Sending the entire shipment back was a way of keeping the supplier occupied, so that they need to keep people on payroll, who would be needed in a war.
The thing about the in-country units, was actually a form of training - you want each unit to know how to accomplish the entire task. Sure you could use the previous work, but then the incoming unit would not know how to do it. Plus it keeps the incoming unit busy, and everyone, and everything else associated with it, both busy, and in practice.
A unit commander has a big problem: how do I keep my soldiers both busy and trained. The simplest way to do that is to make them redo things someone else already did.
Try looking at all the inefficiency in this light, and it will all make sense.
PS. Were you ever a commander/officer (not sure of the right term)? Or did you ever keep children occupied in the summer?