definiens: means the gross amount invoiced on sales of Products within the Territory, less reasonable andcustomary deductions for ( a ) credits for returns, including withdrawals and recalls ; ( b ) sales rebates and chargebacks ; ( c ) sales, value - added and other taxes ( but in the case of value added taxes only to the extent such taxes are not reimburseable orrefundable ) ; ( d ) customs duties on sales made by such seller to the customer ; ( e ) wholesaler fee - for - service discounts ; and(f ) group purchasing organization ( GPO ) fees ; but in the case of ( a ) and ( b ) only to the extent accrued under accountingprinciples generally accepted in the U.S. for deductions to be actually given to and taken by the customer, and in the case of(c ) and ( d ) only to the extent separately itemized in the invoice to and paid by the customer