An underpayment can occur only with respect to a period for which a recipient filed an application, if required, for benefits and met all conditions of eligibility for benefits. An underpayment, including any amounts of State supplementary payments which are due and administered by the Social Security Administration, is:
(a) Nonpayment, where payment was due but was not made; or
(b) Payment of less than the amount due. For purposes of this section, payment has been made when certified by the Social Security Administration to the Department of the Treasury, except that payment has not been made where payment has not been received by the designated payee, or where payment was returned.