"[A] Merger Agreement that provided that Berkshire would not cause Acme to reduce pension benefits for 12 months, or reduce the employer contributions pursuant to the plan. There was no time limit on the later obligation.... [In] 2014 Berkshire gave Acme an ultimatum that the Plan had to be amended (either to reduce employer contributions or to allow for such changes in the future), or Berskshire would divest itself of Acme. Acme made the change Berkshire requested.... The court noted: '[a]n employer can impose extra-ERISA contractual obligations upon itself, and when it does so, these extra-ERISA obligations are rendered enforceable by contract law.' " [Hunter v. Berkshire Hathaway, Inc., No. 15-10854 (5th Cir. July 11, 2016)]