definiens: means the amount invoiced or otherwise billed by S igma or SAGE for sales or other commercial disposition of a Licensed Product in the Field to a Third Party purchaser, less the following to the extent included in such billin g or otherwise actually allowed or incurred with respect to such sales : ( a ) discounts, including cas h, trade and quantity discounts, price reduction programs, retroactive price adjustments with respec t to sales of a product, charge - back payments and rebates granted to trade customers ; ( b ) credits or allowances actually granted upon rejections or returns of Licensed Products, including for reca lls or damaged goods ; ( c ) freight, postage, shipping and insurance charges actually allowed or paid for delivery of Licensed Products, to the extent billed ; ( d ) customs duties, surcharges and o ther governmental charges incurred in connection with the exportation or importation of a Licensed Product ; ( e ) taxes, duties or other governmental charges levied on, absorbed or otherwi se imposed on sale of Licensed Products, including without limitation value - added taxes, or other governmental charges otherwise measured by the billing amount, when included in bi lling, as adjusted for rebates and refunds, but specifically excluding taxes based on net income of the seller ; and ( f ) a reasonable allowance for bad debts ( such allowance not to exceed 2 % of gross sales ) provided that all of the foregoing deductions are calculated in accordance with genera lly accepted accounting principles consistently applied throughout the selling party ’s organization . ” 2 7