All acceptances of cash settlements by the Commissioner of Indian Affairs for livestock lent by the United States to any individual Indian, or to any tribe, association, corporation, or other group of Indians, and all sales and relending of livestock repaid in kind to the United States on account of such loans are authorized and ratified: Provided, That on and after May 24, 1950, the value of such livestock for the purposes of any such cash settlement shall be based on prevailing market prices in the area and shall be ascertained by a committee composed of three members, one of whom shall be selected by the superintendent of the particular agency, one of whom shall be selected by the chairman of the tribal council, and one of whom shall be selected by the other two members.