Payments to contractors.

(a) Funds advanced to the Secretary of the Interior for the Uprating Program and costs reasonably incurred by the Contractor in advancing such funds, as approved by Western, shall be returned to the Contractor advancing the funds during the Contract period through credits on that Contractor's power bills. Appropriate credits will be developed and applied pursuant to terms and conditions agreed to by contract or agreement. (b) All other obligations of the United States to return funds to a Contractor shall be repaid to such Contractor through credits on power bills, with or without interest, pursuant to terms and conditions agreed to by contract or agreement.