determines that the negotiated price of a PDP sponsor applied at the point-of-sale with respect to a covered part D drug for a year dispensed by a pharmacy was not equal to the total reimbursement made to such pharmacy for such drug for such year (taking into account any incentive payments and adjustments and pharmacy price concessions, regardless of when such payments and adjustments or price concessions were applied), such sponsor shall, not later than 90 days after receiving notice of such determination, furnish to the pharmacy that dispensed such drug and to the Secretary a written explanation of why such negotiated price was not equal to such reimbursement. (V) Definitions In this clause: (aa) Incentive payments and adjustments The term incentive payments and adjustments means, with respect to payment to a pharmacy by a PDP sponsor for a covered part D drug, any prospective or retrospective price concessions, rebates, discounts, fees, reconciliation adjustments, bonuses, performance payments, incentives, and any other adjustment to such payment determined through the use of a quality measure, and any other adjustment made with respect to such payment, regardless of when such payments and adjustments are applied. Such term does not include any manufacturer rebates or concessions made with respect to such drug. (bb) PDP sponsor The term PDP sponsor includes an MA organization offering an MA–PD plan under part C and an entity that contracts with such sponsor or organization, such as a pharmacy benefit manager. (cc) Quality measure The term quality measure means performance criteria established by a PDP sponsor (including an entity that contracts with such sponsor, such as a pharmacy benefit manager) to determine the amount or applicability of incentive payments and adjustments. (iii) Quality measure working group (I) In general Not later than September 1, 2018, the Secretary shall convene a quality measures working group (in this clause referred to as the working group ) for purposes of establishing quality