Consistent with the requirements of Section 401(a)(2) of the Internal Revenue Code (26 U.S.C. Sec. 401(a)(2)), the corpus or income of the plan’s trust shall not be diverted to, or used for, purposes other than the exclusive benefit of the members or their beneficiaries nor shall there be a reversion of trust funds except as permitted by Revenue Ruling 91-4, 1991-1 C.B. 57, by the Internal Revenue Service.