"[T]he assumptions and methods used to calculate the interest rate assumption for purposes of withdrawal liability [under the MPPAA] must be those in effect as of the Measurement Date.... Were it otherwise, the selection of an interest rate assumption after the Measurement Date would create significant opportunity for manipulation and bias.... Absent any change to the previous plan year's assumption made by the Measurement Date, the interest rate assumption in place from the previous plan year will roll over automatically." [The National Retirement Fund, et al. v. Metz Culinary Management, Inc., No. 17-1211 (2d Cir. Jan. 2, 2020)]