Whenever an Indian tribe requests retrocession of any program for which assistance is provided under this subchapter, such retrocession shall become effective upon a date specified by the Secretary not more than 120 days after the date on which the tribe requests the retrocession, or such later date as may be mutually agreed upon by the Secretary and the tribe. If such a program is retroceded, the Secretary shall provide to any Indian tribe served by such program at least the same quantity and quality of services that would have been provided under such program at the level of funding provided under this subchapter prior to the retrocession. The tribal governing body requesting the retrocession shall specify whether the retrocession shall be to a contract administered by the tribe, or a tribal entity, under the authority of the Indian Self-Determination Act [
25 U.S.C.
450f et seq.] or to a Bureau administered program.