(f) Adjusting billing prices. Pending execution of the contract modification (see paragraph (e) of this section), the Contractor shall submit invoices or vouchers in accordance with billing prices stated in this contract. If at any time it appears that the then-current billing prices will be substantially greater than the estimated final prices, or if the Contractor submits data showing that the redetermined prices will be substantially greater than the current billing prices, the parties shall negotiate an appropriate decrease or increase in billing prices. Any billing price adjustment shall be reflected in a contract modification and shall not affect the redetermination of prices under this clause. After the contract modification for price redetermination is executed, the total amount paid or to be paid on all invoices or vouchers shall be adjusted to reflect the agreed-upon prices, and any resulting additional payments, refunds, or credits shall be made promptly.