The Commissioner of Social Security is authorized to reimburse the State agency administering or supervising the administration of a State plan for vocational rehabilitation services approved under title I of the Rehabilitation Act of 1973 [29 U.S.C. 720 et seq.] for the costs incurred under such plan in the provision of rehabilitation services to individuals who are referred for such services pursuant to subsection (a), (1) in cases where the furnishing of such services results in the performance by such individuals of substantial gainful activity for a continuous period of nine months, (2) in cases where such individuals receive benefits as a result of section 1383(a)(6) of this title (except that no reimbursement under this subsection shall be made for services furnished to any individual receiving such benefits for any period after the close of such individual’s ninth consecutive month of substantial gainful activity or the close of the month with which his or her entitlement to such benefits ceases, whichever first occurs), and (3) in cases where such individuals, without good cause, refuse to continue to accept vocational rehabilitation services or fail to cooperate in such a manner as to preclude their successful rehabilitation. The determination that the vocational rehabilitation services contributed to the successful return of an individual to substantial gainful activity, the determination that an individual, without good cause, refused to continue to accept vocational rehabilitation services or failed to cooperate in such a manner as to preclude successful rehabilitation, and the determination of the amount of costs to be reimbursed under this subsection shall be made by the Commissioner of Social Security in accordance with criteria determined by the Commissioner in the same manner as under section 422(d)(1) of this title.