As soon as possible after the appropriation of judgment funds and pending approval of a plan or the enactment of legislation authorizing the use or distribution of the funds, the Commissioner shall invest such funds pursuant to 25 U.S.C. 162a. Investments of judgment funds and of investment income therefrom will continue to be made by the Commissioner after the approval of a plan or enactment of use or distribution legislation to the extent funds remain available for investment under such plan or legislation, and provided that thereafter investments of judgment funds made available for tribal use are not undertaken by the tribe pursuant to authorizing law. Invested judgment funds, including investment income therefrom, shall be withdrawn from investment only as currently needed under approved plans or legislation authorizing the use or distribution of such funds.