definiens: shall mean the amount billed by Chiron or its Affiliates orsublicensees to third parties for the sale of Royalty Products or performance ofassays using Royalty Products, less discounts allowed ; less credits for customers'rerurns and allowances ; less the value of the instrument and service componentsof an operating or capital lease"for which the charges are included in the price ofRoyalty Products'purcbased by the lessee ; less charges for freight handlmgandless sales and use taxes and other similar taxesincurred, all to the extent reasonable and as determined in accordance withgenerally accepted accounting practices and industry practices _ Notwithstandingthe foregoing, if Chircn or its Affiliates or sublicensees bills a third party forperformance of an assay using a Royalty Product, the amount of Net SalesRevenue shall be equal to the average Net Sales Revenue for sales of such Royaltyassay is performed, or, if such Royalty Product is not sold forcommercial use in such country during such quarter, the worldwide average Net . .~