(a) A Federal employee assigned under this part must agree, as a condition of accepting an assignment, to serve with the Federal Government upon completion of the assignment for a period equal to the length of the assignment.

(b) If the employee fails to carry out this agreement, he or she must reimburse the Federal agency for its share of the costs of the assignment (exclusive of salary and benefits). The head of the Federal agency, or his or her designee, may waive this reimbursement for good and sufficient reason.