48 CFR §817.7004-3

1. (a)UCAs shall contain definitization schedules that provide for definitization by the earlier of—
   1. (1)The date that is 180 days after issuance of the action (this date may be extended but may not exceed the date that is 180 days after the contractor submits a definitization proposal); or
   2. (2)The date on which the amount of funds paid to the contractor under the contract action is equal to more than 50 percent of the not-to-exceed price.
2. (b)Submission of a definitization proposal in accordance with the definitization schedule is a material element of the contract. If the contractor does not submit a timely definitization proposal, the contracting officer may suspend or reduce progress payments under FAR 32.503-6, or take other appropriate action.