Except as provided in subsection (b) of this section, a banking institution shall be open for business on each day during the year except for the days on which the banking institution is required or authorized by this subtitle to be closed. The Commissioner may approve the operation of a branch that is open for business fewer days than described in subsection (a) of this section if the Commissioner determines that: The branch will serve a customer base or community that has unique banking needs; At least 1 other branch of the banking institution is open for business as described in subsection (a) of this section; and The operation of the branch will not be detrimental to the public interest or to banking institutions.