Rating plans for auto insurance

14. a. Every insurer transacting or proposing to transact private passenger automobile insurance may file one or more rating plans in the voluntary market. Every insurer writing private passenger automobile insurance in this State which intends to write coverage in the voluntary market using more than one rate level shall file with the commissioner the rates and underwriting rules which are applicable to each rate level. b. An insurer which intends to use more than one rating plan may make an initial filing for additional rating plans which are based on a percentage increase or decrease of the existing rate level in its current rating plan. c. Notwithstanding any other law to the contrary, any initial rates filed pursuant to subsection b. of this section shall be deemed to be approved if not disapproved by the commissioner within 120 days of receipt of the filing by the department. Any subsequent modification of any rate level, or any initial rate level which is not based on a percentage increase or decrease of an existing rate level as provided for in this section, shall be subject to the provisions of P.L.1944, c.27 (C.17:29A-1 et seq.). d. Any limitation on rates established by the provisions of section 7 of P.L.1983, c.65 (C.17:29A-36) shall apply separately to each rate level established pursuant to subsection a. of this section.