(a) The Secretary may require proof of continuance of total disability at any time the Secretary may deem same necessary. In the event it is found that an insured is no longer totally disabled, the waiver of premiums shall cease as of the date of such finding, and the insurance may be continued by payment of premiums, the due date of the first premium payable being the next regular monthly due date of the premium under the policy. The insurance shall not lapse prior to the date of expiration of the grace period allowed for the payment of such premium or prior to the expiration of 31 days after date of notice to the insured of the termination of the premium waiver, whichever is the later date. Such notice shall be sent by registered mail or by certified mail and sufficient notice will be deemed to have been given when such letter has been placed in the mails by the Department of Veterans Affairs: Provided, That the Secretary may grant an additional period of not more than 31 days for payment of the premiums in any case in which it is shown that the failure to make payment within 31 days after notice as defined in this paragraph was due to circumstances beyond the insured's control; but the premiums in any such case must be paid during the lifetime of the insured. The failure of the insured to furnish a correct current address at which mail will reach him or her promptly shall not be grounds for a further extension of time for payment of premiums under this section.

(b) In the event a finding that insured is no longer totally disabled is made at the same time a finding is made of total disability entitling the insured to a waiver of premiums while so disabled, the waiver of premiums shall cease as of the date on which total disability ceased and continuance of the insurance in such cases shall be subject to the timely payment of the premiums as they become or have become due and payable. The due date of the first premium payable subsequent to the date total disability ceased is the next regular due date of the premium under the policy, and if such premium was not paid within 31 days after the due date, the insurance lapsed.

(c) If the insured shall fail to cooperate with the Secretary in securing any evidence he may require to determine whether total disability has continued, the premium waiver shall cease effective as of the date finding is made of such failure to cooperate, and the insurance may be continued by payment of the premiums within 31 days after notice of termination as provided in paragraph (a) of this section.