Because they can ... The Registered Real Estate Broker can be multiple licensed by State Law and they may all have differing business models, offerings and services ... Mind you, does sound a little strange to do this though unless trying to "cloak" investments/partners ...???
We own a real estate boutique in Coral Gables and I guess I would imagine if the Broker would like to keep the unique feel of a small firm and avoid the big franchise feel to it, he/she might open new offices under different names. Also, considering plans of selling the brokerage divisions to partners involved in separate offices she/he might keep different names.