A franchising authority may require the production of proprietary information to make a rate determination in those cases where cable operators have submitted initial rates for review or have proposed rate increases. The franchising authority shall state a justification for each item of information requested and, where related to an FCC form filing, indicate the question or section of the form to which the request specifically relates. Upon request to the franchising authority, the parties to a rate proceeding shall have access to such information, subject to the franchising authority's procedures governing non-disclosure by the parties. Public access to such proprietary information shall be governed by applicable state or local law.