(a) There shall be a provision that if the age of the insured or of any other person whose age is considered in determining the premium has been misstated, any amount payable or benefit accruing under the policy shall be such as the premium would have purchased at the correct age.
(b) As to overstatement of age, the policy may provide, in lieu of the provisions required under subsection (a) of this section, that the insurer will refund any excess of premium collected for the amount of insurance or benefit stated in the policy, as based upon the correct age.