(1) This chapter applies only to domestic insurers transacting life, disability, or loss of position insurances, as defined in section 6406, on the cooperative or assessment plan.

  (2) Corporations heretofore organized and/or doing business under the provisions of Act No. 339 of the Public Acts of 1937, as amended, shall hereafter be subject to the provisions of this chapter and shall hereafter be classified as insurers doing business under this chapter.