definiens: shall mean, with respect to the KUDCO Product, the gross amount invoiced to Third Parties for the KUDCO Product in the Territory, less provisions for : ( a ) reasonable and customary trade discounts, promotional allowances, cash discounts, customer refunds and credits ( excluding returns, which are treated below ), customer and government rebates and any other similar allowances which 03345 - 00/0778 effectively reduce the net selling price to the extent incurred and as evidenced and supported by written arrangements ; ( b ) returns based on KUDCO ’s historical experience, currently estimated at 2 %, and speciﬁc returns when known, probable and estimable, and in excess of the existing allowance, ( 0 ) chargebacks based upon historical experience and/or similar experience with existing single source or multi - source generic products ( as then applicable ) adjusted on a timely basis for known and estimable events as evidenced by written arrangements ; and ( d ) speciﬁc retroactive price or shelf stock adjustments and price equalizations when known, probable and estimable