20 C.F.R. § 725.545 – Underpayments.

(a) General. As used in this subpart, the term “underpayment” includes a payment in an amount less than the amount of the benefit due for such month, and nonpayment where some amount of such benefits is payable.
(b) Underpaid individual is living. If an individual to whom an underpayment was made is living, the deficit represented by such underpayment shall be paid to such individual either in a single payment (if he or she is not entitled to a monthly benefit or if a single payment is requested by the claimant in writing) or by increasing one or more monthly benefit payments to which such individual becomes entitled.
(c) Underpaid individual dies before adjustment of underpayment. If an individual to whom an underpayment was made dies before receiving payment of the deficit or negotiating the check or checks representing payment of the deficit, such payment shall be distributed to the living person (or persons) in the highest order of priority as follows:
1. (1) The deceased individual's surviving spouse who was either:
  1. (i) Living in the same household with the deceased individual at the time of such individual's death; or
  2. (ii) In the case of a deceased miner, entitled for the month of death to black lung benefits as his or her surviving spouse or surviving divorced spouse.
2. (2) In the case of a deceased miner or spouse his or her child entitled to benefits as the surviving child of such miner or surviving spouse for the month in which such miner or spouse died (if more than one such child, in equal shares to each such child).
3. (3) In the case of a deceased miner, his parent entitled to benefits as the surviving parent of such miner for the month in which such miner died (if more than one such parent, in equal shares to each such parent).
4. (4) The surviving spouse of the deceased individual who does not qualify under paragraph (c)(1) of this section.
5. (5) The child or children of the deceased individual who do not qualify under paragraph (c)(2) of this section (if more than one such child, in equal shares to each such child).
6. (6) The parent or parents of the deceased individual who do not qualify under paragraph (c)(3) of this section (if more than one such parent, in equal shares to each such parent).
7. (7) The legal representative of the estate of the deceased individual as defined in paragraph (e) of this section.
(d) Deceased beneficiary. In the event that a person, who is otherwise qualified to receive payments as the result of a deficit caused by an underpayment under the provisions of paragraph (c) of this section, dies before receiving payment or before negotiating the check or checks representing such payment, his or her share of the underpayment shall be divided among the remaining living person(s) in the same order or priority. In the event that there is (are) no other such person(s), the underpayment shall be paid to the living person(s) in the next lower order of priority under paragraph (c) of this section.
(e) Definition of legal representative. The term “legal representative,” for the purpose of qualifying for receipt of an underpayment, generally means the executor or the administrator of the estate of the deceased beneficiary. However, it may also include an individual, institution or organization acting on behalf of an unadministered estate, provided the person can give the Office good acquittance (as defined in paragraph (f) of this section). The following persons may qualify as legal representative for purposes of this section, provided they can give the Office good acquittance:
1. (1) A person who qualifies under a State's “small estate” statute; or
2. (2) A person resident in a foreign country who under the laws and customs of that country, has the right to receive assets of the estate; or
3. (3) A public administrator; or
4. (4) A person who has the authority under applicable law to collect the assets of the estate of the deceased beneficiary.
(f) Definition of “good acquittance.” A person is considered to give the Office “good acquittance” when payment to that person will release the Office from further liability for such payment.