I spotted this old thread at Google Maps Help that has very useful information and yet, we have not covered it (go figure). In short, the thread goes through the possibility of having a single business listed in your Google Local Business Center console multiple times. The questions are:

(1) Do you delete the repetitive listings?
(2) If so, which ones?
(3) If not, do you make sure they are in sync with each other?

For example, I have duplicate listings, two unverified, which I am afraid to delete:

Back in March, Joel H. from the Google Maps team wrote:

Forum discussion at Google Maps Help.

Update: You also 100% want to check out Mike B’s post on this.

Update 2: See Joel’s comment (he works at Google):