the present value of the plan’s liabilities, determined in accordance with the rules prescribed by the Pension Benefit Guaranty Corporation under sections 4219(c)(1)(D) and 4281 of Employee Retirement Income and Security Act for multiemployer plans terminating by mass withdrawal, as in effect for the date of the determination, except the plan’s reasonable assumption regarding the starting date of benefits may be used. (3) Other applicable rules Except as provided in paragraph (2), actuarial determinations and projections under this section shall be based on the rules in section 432(b)(3) and section 438(b). 440B. Mergers and asset transfers of composite plans (a) In general Assets and liabilities of a composite plan may only be merged with, or transferred to, another plan if— (1) the other plan is a composite plan, (2) the plan or plans resulting from the merger or transfer is a composite plan, (3) no participant’s accrued benefit or adjustable benefit is lower immediately after the transaction than it was immediately before the transaction, and (4) the value of the assets transferred in the case of a transfer reasonably reflects the value of the amounts contributed with respect to the participants whose benefits are being transferred, adjusted for allocable distributions, investment gains and losses, and administrative expenses. (b) Legacy plan (1) In general After a merger or transfer involving a composite plan, the legacy plan with respect to an employer that is obligated to contribute to the resulting composite plan is the legacy plan that applied to that employer immediately before the merger or transfer. (2) Multiple Legacy Plans If an employer is obligated to contribute to more than one legacy plan with respect to employees eligible to accrue benefits under more than one composite plan and there is a merger or transfer of such legacy plans, the transition contribution rate applicable to the legacy plan resulting from the merger or transfer with respect to that employer shall be determined in accordance