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 for which are payable monthly, 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 and unpaid premiums may be deducted from any settlement under the policy.