D.C. Mun. Regs. r. 27-3341
The costs of employee services based on a labor-management agreement shall be allowable only to the extent that the contracting officer determines that the agreement does not discriminate against the District, and the personnel costs are warranted by the character and circumstances of the work performed under the contract. A labor-management agreement shall be deemed to discriminate against the District if it results in employee compensation in any form that is in excess of compensation paid for non-District work under similar circumstances.
The contracting officer shall not disallow costs for compensation resulting from labor-management agreements unless the contractor has been permitted an opportunity to justify the costs, and consideration has been given to whether unusual conditions pertain to the District contract work which imposes burdens, hardships, or hazards on the contractor's employees for which compensation that might otherwise appear unreasonable is required to attract and hold necessary personnel,
D.C. Mun. Regs. r. 27-3341