(a) If its articles of incorporation so provide, a domestic mutual insurer on the cash premium plan may, while it is authorized to issue policies without contingent liability to assessment, issue policies not entitled to participate in the insurer's savings and earnings.
(b) Such insurer shall not issue in this territory both participating and nonparticipating policies for the same class of risks; except, that both participating and nonparticipating life insurance policies may be issued if the right or absence of the right to participate is reasonably related to the premium charged.