To experiment with this, I imported a gedcom of a small portion of my database into RootsMagic.
I then uploaded that database to Ancestry, creating a new tree. Within that tree, I looked at the hints for Albert Hutchinson.
On the RootsMagic side, TreeShare indicated that there were three new 'Residence' facts on Ancestry that were not in RootsMagic.
Working with the 1850 residence fact, I selected 'Add as new event in RootsMagic' and accepted the changes.
In RootsMagic, the source screen for the 1850 Residence fact contains the newly downloaded census information.
Editing that source reveals a new master source: 1850 United States Federal Census. This source is using the 'Ancestry Record' template.
The 'Ancestry Record' template appears to follow guidelines for citing a book.
The source list reveals that the citations will be 'lumped' together under the broad title of the database:
This handling of downloaded sources is much cleaner than what I experienced mid-beta testing.