Overpayments. Upon determination that an overpayment has been made, SSA shall make adjustments against future federally administered payments for which the individual is entitled. The rules and requirements in effect for recovery of SSI benefits shall also apply to the recovery of mandatory State supplement overpaid amounts. Underpayments. Upon determination that an underpayment of the State supplement is due and payable, the SSA shall pay the underpaid amount to the underpaid claimant or to the individual's representative. If the underpaid individual dies before receiving the underpaid amount of the State supplement, the underpaid amount shall be paid to the individual's eligible spouse. If the deceased claimant has no eligible spouse, the underpaid amount may not be paid.