; (7) $50,000,000 shall be made available for the mobility demonstration authorized under section 238 of this title, of which up to $20,000,000 shall be for new incremental voucher assistance and the remainder of which shall be available to provide mobility-related services to families with children, including pre- and post-move counseling and rent deposits, and to offset the administrative costs of operating the mobility demonstration: Provided , That incremental voucher assistance made available under this paragraph shall be for families with children participating in the mobility demonstration and shall continue to remain available for families with children upon turnover: Provided further , That for any public housing agency administering voucher assistance under the mobility demonstration that determines that it no longer has an identified need for such assistance upon turnover, such agency shall notify the Secretary, and the Secretary shall recapture such assistance from the agency and reallocate it to any other public housing agency or agencies based on need for voucher assistance in connection with such demonstration