employer shall pay wages to a covered employee provided by another employer to perform labor for the employer, or allow a covered employee provided by another employer to perform labor for the employer at wages, at a rate less than the prevailing rate at which the employer for whom the labor is performed pays wages to direct employees for similar work on jobs the performance of which requires similar skill, effort, and responsibility, and which are performed under similar working conditions, except as provided in subparagraph (B). (B) Exceptions An employer may pay a covered employee a wage at a rate less than the wage rate required under subparagraph (A) if— (i) such payment is made pursuant to— (I) a seniority system