Where -

(a) in respect of any period that a designated person or deciding officer has granted supplementary welfare allowance to or in respect of a person who, though entitled under the legislation of a Member State (other than the State) or the United Kingdom to a social security payment (in this section referred to as "the relevant payment"), is not in receipt of such payment, and

(b) the supplementary welfare allowance is in excess of the amount which would have been granted to that person if he or she had been in receipt of the relevant payment, and

(c) the designated person or deciding officer has certified to the competent institution of the relevant Member State or the United Kingdom the amount of supplementary welfare allowance in excess of which the person would have been entitled (in this section referred to as "the excess") in respect of that period,

the designated person or deciding officer may request that competent institution to deduct the amount of the excess from the relevant payment.