For advances, the operative event for the exchange rate shall be the operative event applicable to the price or amount to which the advance relates, where this event has occurred by the time the advance is paid, or, in other cases, the date of setting in euro of the advance or, failing that, the date of payment of the advance. The operative event for the exchange rate shall be applied to advances without prejudice to the application to the entire price or amount in question of the operative event for that price or amount.