(8)Where an import licence is also used to administer a tariff quota to which preferential arrangements apply, such preferential arrangements are to apply to importers by virtue of the licence which must, in some cases, be accompanied by a document from a third country. To avoid any overrun in the quota, the preferential arrangement is to apply up to the quantity for which the licence was issued. In such cases a tolerance should be permitted, provided that the part of the quantity exceeding the quantity shown on the licence but within the tolerance does not benefit from the preferential arrangement and the conventional customs duty is payable.