That's not my point at all. I'll try to be a little more specific about what I meant:
Let's say that I have five slots in my backpack that I always keep firmly filled. It does not matter if with or without mod. At least one of these slots is reserved for ammunition of my current ranged weapon. So far so good. Now Hordenight begins. I was well prepared and had put additional ammunition in my backpack. What happens now? Of course the ammunition in the front slots will be used up first. This creates "gaps" in the backpack very quickly. My fixed ammunition slot is then empty. If I now take a few drops in between, this slot is occupied randomly. It can happen that after a horde night I clean out the loot of the night and overlook the fact that my fixed ammo slot is now wrongly occupied.
If the ammunition would be used up first from the rear slots, this would not be a problem anymore. First World Problem - I know! I'd still consider it a useful improvement if you could at least somehow can have control about it.