; and (2) the employee of such private-sector organization whose position is being temporarily occupied by the employee of the Department under paragraph (1) to temporarily occupy the position at the Department of the employee of the Department who is being temporarily assigned under paragraph (1). (b) Agreements (1) The Secretary shall provide for a written agreement among the Department, the private-sector organization, and the employees concerned regarding the terms and conditions of the employees’ assignment under this section. The agreement— (A) shall require that the employee of the Department, upon completion of the assignment, will serve in the Department; (B) shall provide that if the employee of the Department or of the private-sector organization (as the case may be) fails to carry out the agreement, such employee shall be liable to the United States for payment of all expenses of the assignment, unless that failure was for good and sufficient reason, as determined by the Secretary