definiens: shall mean for each [ DELETED ] of EPOGEN purchased by a Qualified Customer in any Quarter under an [COMPANY] Dialysis Contract, the [ DELETED ] in effect on the date of purchase [ DELETED ] all of the discounts and rebates per [ DELETED ] of EPOGEN that, for such Q uarter were actually earned by such Qualified Customer pursuant to the terms of such [COMPANY] Dialysis Contract ( regardless of the actual Quarter in which such discounts or rebates are actually paid to such Qualified Customer ) ; provided, that if any such disc ounts and rebates once paid are subsequently returned, revised or withdrawn, including pursuant to any retroactive amendment of the [COMPANY] Dialysis Contract or payment settlement ( whether in such Quarter or any subsequent Quarter ), the applicable shall be based on the discounts, rebates and chargebacks taking into full account such returns, revisions or withdrawals