41 CFR § 101-26.506-5
Reimbursement for services
June 9, 2020
If the GSA proposal is acceptable, a purchase order, requisition, or other funded authorization document shall be issued to the GSA office named in the proposal. GSA will bill the office indicated in the order or authorization for the amount specified in the proposal. The reimbursement procedures are designed to recover GSA's direct cost for providing these services. Any changes in the scope of the project requested by the requisitioning agency prior to its completion may require a revision in the amount of the reimbursable charges and the time schedule for completion.
[31 FR 9797, July 20, 1966]