; and (2) except as otherwise provided by such Secretary based on the size of the overpayment, to treat a contribution of an inadvertent overpayment which would qualify as a rollover under section 402(c), 403(a)(4), 403(b)(8), or 457(e)(16) of the Internal Revenue Code of 1986 but for the fact that it is an overpayment as a rollover contribution for all purposes under such Code. No inference is intended regarding the existence in any particular situation of an obligation for any person to pay a plan for an overpayment. (b) Overpayments under ERISA Not later than December 31, 2018, the Secretary of Labor shall prescribe rules under which no fiduciary of a plan shall have a duty under part 4 of title I of the Employee Retirement Income Security Act of 1974 to seek recoupment from a participant or beneficiary of an inadvertent overpayment (within the meaning of such term as used in subsection (a)), provided that, if a repayment is required, such overpayment is paid back by the plan sponsor or other person. (c) Overpayments by PBGC Effective for overpayments made to a participant or beneficiary after December 31, 2018, the Pension Benefit Guaranty Corporation shall not reduce future payments with respect to the same participant or beneficiary by more than 10 percent in recouping such overpayment. 308. Treatment of custodial accounts on termination of section 403 (b) plans (a) In general Not later than 6 months after the date of the enactment of this Act, the Secretary of the Treasury shall issue guidance to provide that, if an employer terminates the plan under which amounts are contributed to a custodial account under subparagraph (A) of section 403(b)(7) of the Internal Revenue Code of 1986— (1) the plan administrator or custodian may distribute an individual custodial account in kind to a participant or beneficiary of the plan, and (2) the distributed custodial account shall be maintained by the custodian on the same basis as a custodial account to which section 403(b)(7) of such Code applies, similar to the