ORIGINAL: el cid again
If you do make a supply model then there need to be (remember, this is at a minimum) two different versions of the stuff: guns and butter.
For what it is worth, I recommended a slightly different supply model during the design phase. I feel there should be more than two kinds of resources (resources and oil) and more than two kinds of mulitary supply (supply points and fuel). But I knew I could never sell a model as complex as you advocate, so I tried for just three kinds of military supply (fuel - which is all POL - ammo - which is everything but small arms munitions - and general supply - which is everything else the military needs). I also advocated a set of simple resources (iron, coal, bauxite, oil, etc) - without saying how many should be adopted. I have made such models work fairly well. But UNTIL we get to play with code, it isn't an option for us. I think we can make this system work better. Otherwise I would not try.
Actually most of this has been hashed out in previous threads/postings. Indeed you have stated much of what my arguments have been when it comes to pure military locistics. The key to all this is that it is mostly academeic due to its ingrained nature code wise.