Employee benefits brokerage firm Cowan Benefits is moving its headquarters from Franklin to Brentwood. By mid-April the firm will relocate its 80 employees from Franklin's Dover Center at 113 Seaboard Lane to Boyle Investment Company's Centre Court Building at 5110 Maryland Way in Brentwood, according to a news release. The firm will occupy 15,000 square feet on the second and third floors of the building. Additional expansion is also possible. " We are excited about the new office. It allows us…