They have different reasoning, most likely it has to do with performance/store conditions of one of the managers. Store Manager used to never be moved, as they wanted them to build a deep connection with the community. Store Managers are the ultimate scapegoat for un-effective company programs, they are just expected to get it down and figure it out. Store have come more and more political, the higher ups want you to just be a "YES MAN". There is a reason why Store Managers are younger and younger every year, plus Co-Managers normally only last 1 year.
One of mine just got a promotion last night. Which is kind of nice in it's own way and might even be at a store closer to where she lives. But all the same I'm kind of happy to see her go. That woman looked like she came out the womb with resting *itch face. Never smiled or had too much of a nice response when someone would ask how she was doing, til I saw her at the holiday Christmas party last year and one time last week. But I guess that was only do to her finding out she will be moving on. Good luck to her, and the new store she heads into.