Excerpt: On April 18, the Internal Revenue Service ... and U.S. Treasury Department ... released Rev. Proc. 2005-23 which provides guidance to plans affected by a U.S. Supreme Court decision regarding plan amendments that add or expand a suspension of benefits provision. In Central Laborers' Pension Fund v. Heinz, 124 S. Ct. 2230 (June 7, 2004), the Supreme Court held that a plan amendment that expanded the reasons for suspension of benefit payments retirees had already accrued could not[.]