Except as provided in subsection (b) of this section, a premium increase under long-term care insurance may not be based on the age of the insured or certificate holder. A carrier may impose an across-the-board premium increase on policies or contracts of long-term care insurance that the carrier issues or delivers in the State after the carrier: submits to the Commissioner an actuarial memorandum that supports the proposed premium increase; and obtains the approval of the Commissioner. This section does not prohibit age-banding.