Another reason you may see multiple msc's shopping for the same company is because sometimes the stores/restaurants/etc are franchises.
For example, a burger chain has franchise locations owned by the same franchisee 25 miles around me. The locations beyond that are owned by someone else, whether corporate or other franchises.
Consequently, one msc has the shop for the local franchisee, while all the other locations witin 200 miles are shopped by a different msc.
Obviously the franchise explanation does not apply to banks, but it is true for many other types of locations.