This excerpt taken from the PNK 8-K filed Nov 30, 2007.
§ 8.1.8 Costs, other than costs included in Change Orders approved by the Owner, that would cause the Guaranteed Maximum Price to be exceeded.
ARTICLE 9 DISCOUNTS, REBATES AND REFUNDS
§ 9.1 Cash discounts obtained on payments made by the Contractor shall accrue to the Owner. Trade discounts, rebates, refunds, and similar discounts and amounts received from sales of surplus materials and equipment shall accrue to the Owner, and the Contractor shall make all necessary provisions so that they can be secured.