. For any calendar year after its first two full calendar years of operation, no domestic mutual insurer, other than one issuing nonassessable policies, shall incur any costs or expense in the writing or administration of property, accident and health or sickness, and casualty insurances, other than boiler and machinery or elevator, transacted by it which, exclusive of losses paid, loss adjustment expenses, investment expenses, dividends, and taxes exceeds the sum of:
(1) Forty per cent of the net premium income during that year after deducting therefrom net earned reinsurance premiums for the year, plus
(2) All of the reinsurance commissions received on reinsurance ceded by it.