Where a competent authority or competent institution of one Party has made a payment of any benefit to a person for any period, or event, in advance of the period, or event, to which it relates or has paid him any benefit for a period, or event, whether by virtue of this Convention or otherwise, and the competent authority or the competent institution of the other Party afterwards decides that the person is entitled to benefit for that period, or event, under its legislation, the competent authority or the competent institution of the latter Party, at the request of the competent authority or the competent institution of the former Party, shall deduct from the benefit due for that period, or event, under its legislation any overpayment which, by virtue of this Convention, results from the advance payment of benefit, or from the benefit paid, by the competent authority or the competent institution of the former Party and shall, where appropriate, transmit this sum to the competent authority or the competent institution of the former Party.