If the field office (FO), processing center (PC), or a National 800 Number Network
(N8NN) agent receives an inquiry regarding a possible underpaid deceased beneficiary,
review the beneficiary’s master benefit record (MBR) or payment history update system
(PHUS)) to determine if an underpayment is due. If the office determines that there
is no underpayment, explain why no underpayment is due.