(1)    Rate making. An insurer may itself establish rates and supplementary rate information for one or more market segments based on the factors in s. 625.12 and, if the rates are for motor vehicle liability insurance, subject to s. 632.365, or the insurer may use rates and supplementary rate information prepared by a rate service organization, with average expense factors determined by the rate service organization or with such modification for its own expense and loss experience as the credibility of that experience allows.

   (2)   Rate filing. An insurer may discharge its obligation under s. 625.13 (1) by giving notice to the commissioner that it uses rates and supplementary rate information prepared by a designated rate service organization, with such information about modifications thereof as is necessary fully to inform the commissioner. The insurer’s rates and supplementary rate information shall be those filed from time to time by the rate service organization, including any amendments thereto as filed, subject, however, to the modifications filed by the insurer.