(1) In lieu of the requirements of section 2646 for deviation and as an alternative method for deviation every member of or subscriber to a rating organization shall adhere to the filings made on its behalf by such organization except that any such insurer may make application to the commissioner to file a deviation from the class rates, schedules, rating plans or rules respecting any kind of insurance, or class of risk within a kind of insurance, or combination thereof. Such application shall specify the basis for the modification and a copy shall also be sent simultaneously to such rating organization. Every such application shall become effective immediately as of the date filed with the commissioner. In considering the application to file such deviation the commissioner shall give consideration to the available statistics and the principles for rate making provided in section 2603. The commissioner shall issue an order approving of the deviation as filed if he finds it meets the requirements of section 2603. If the commissioner finds that the deviation does not comply with the requirements of this chapter, he may issue an order determining wherein and to what extent such proposal is deemed to be improper and fixing a date thereafter, within a reasonable time, after which such deviation shall no longer be effective. Any order of disapproval under this section must be entered within 30 days of the date the application for the deviation affected is filed with the commissioner. If such deviation shall be disapproved, the insuring provisions of any contract or policy issued prior to the time the order becomes effective shall not be affected. But if the commissioner disapproves such deviation as not being in compliance with section 2603, he may order an adjustment of the premium to be made with the policyholder either by refund or collection of additional premium, if the amount is substantial and equals or exceeds the cost of making the adjustment.

  (2) Each deviation filed and so approved shall remain in effect for a period of not less than 1 year from the effective date unless sooner withdrawn by the insurer with the approval of the commissioner or until terminated in accordance with the provisions of section 2618 or 2620.