There shall be a provision as follows:

"MISSTATEMENT OF AGE OR SEX: If the age or sex of the insured has been misstated, all amounts payable under this policy shall be such as the premium paid would have purchased at the correct age or sex."

The amount of any underpayments which may have been made on account of any such misstatement under a disability income policy shall be paid the insured along with the current payment and the amount of any overpayment may be charged against the current or succeeding payments to be made by the insurer. Interest may be applied to such underpayments or overpayments as specified in the insurance policy form but not exceeding six percent per annum.