May an Agency require the submission of a certificate of cost or pricing pursuant to FAR 15.403-4 when modifying the contract due to overruns that nearly double the original price of the award. (FAR 15.403-2 says cost or pricing data are not required for proposals soley used for overrun funding). The original K was issued pursuant to a BAA. The first overrun proposal was approximately 50% of the original price. This overrun was incorporated into a mod subject to downward negotiations at time of definitization. During the course of negotiations, the contractor informed that a second overrun had occurred. The 2nd proposal was also incorporated into a modification subject to downward negotiations. With this second overrun the price nearly doubled from the original award. Once this is definitized may the agency require a certificate with the confirmation of negotiations.