I disagree that the "special munitions" tag was for both groups of ammo. The memo divides them into priority, the highest priority are all chemical capable, the second priority are not. There is nothing that could be special about this artillery other than chemical, and I am a former artillary officer and have good experience with this subject.
I went back and looked at the memo again, and quite clearly you are right, the "special munitions" went with the larger rounds.
Somehow I've overlooked the initial discussion on this thread about this subject and only noticed it when Ernest pinged me to Powerline.
All the same, this thread is getting enough attention that it doesn't hurt to rehash it. ;-)