There shall be a provision that the insured is entitled to a grace period of four weeks within which the payment of any premium after the first may be made, except, that, in policies the premiums which are payable monthly or less often, the period of grace shall be one month but not less than 30 days, and that during the period of grace the policy shall continue in full force, but if during the grace period the policy becomes a claim, then any overdue premiums may be deducted from any cash payment which may be due under the policy.