This excerpt taken from the GPS 10-Q filed Jun 9, 2009.
27.4 Billing Disputes And Reports
Supplier and Gap shall exercise good faith efforts to resolve all billing disputes to their mutual satisfaction within thirty (30) calendar days; provided, however, that in the event the billing dispute relates to Services provided to Supplier by a Subcontractor and the obligation to pay for such Service is passed through by Supplier directly to Gap, the aforementioned thirty (30) day period shall commence on the date Gap receives the invoice at issue from Supplier. Gap shall be entitled to withhold amounts in dispute under this Section 27.4 (Billing Disputes and Reports) in accordance with Section 26.7 (Withhold Remedy) without Supplier claiming a default of a material duty or obligation by Gap. A billing dispute number will be assigned by Supplier to all billing disputes. The billing dispute number will be used by Supplier and Gap on all correspondence and reports to identify the dispute. Supplier shall provide Gaps Infrastructure Partnership Executive and agency department(s) with a monthly report of the status of pending billing disputes.