"The [federal district] court concluded that because Principal 'bases its calculation of benefits owed to [Mr. Garrett] on rationales not relied on by the claims administrator below and has failed to show special circumstances warranting the supplementation of the administrative record, the [c]ourt will not rely on [Principal's] calculation of benefits owed to [Mr. Garrett].' ... We conclude that the district court properly declined to consider Principal's new arguments.... This rule furthers the goal of ERISA to allow plan administrators and beneficiaries to 'hav[e] a full and meaningful dialogue regarding the denial of benefits. .. [and to prevent the plan administrator from] treat[ing] the administrative process as a trial run and offer[ing] a post hoc rationale in district court.' " [Garrett v. Principal Life Insurance Co., No. 13-6087 (10th Cir. Feb. 18, 2014)]  MORE >>