"each of which I label to reflect the repository (eg. 1910 United States Federal Census [Family History Library]). ACOM source is, of course, the exception."
Why? If you want to say that the information comes from a different Repository you should add a repository record. The source will remain the same, just the place where you found the source changes i.e. "the repository".
Some will argue that you don't need to have a repository for sources that can be found in multiple places, and I half agree, yet for me I like to record the repository anyway so that when I travel to a library in Germany, USA, Norway, England, Iceland etc, or any city that may have information, I like to know what I have found in that library in the past so I can go to it again. In the repository_citation I keep the local library call number so I can actually call the library or archive and request the book or document before I arrive and they can pull it from the stack. Many archives like knowing that I'm coming and what resource I need a day or two before I come. This way thay can, at their conveniance, get information. In some cases the librarian knows me and finds additional stuff that they think will help.