(a) A provider of intrastate operator assisted communications services must file with the commission tariffs setting forth its rates, charges, rules and regulations.

(b) Whenever a provider files new tariffs or proposed changes in tariff rates previously effective, the provider shall file therewith an explanation of the rates or changes and of the basis therefor.

(c) Such tariffs shall not become effective for 75 days; and may, during that 75-day period, be suspended by the commission for a further period of up to eight months for investigation and hearing if the commission determines that the public interest so requires, unless the maximum rates and charges to be charged by a provider do not exceed the highest rates and charges authorized by the commission for use by a local exchange telephone corporation or a dominant interexchange telephone corporation in the State for similar kinds of operator assisted telephone calls.