Before concluding that the district court had not abused its discretion under the specific facts and evidence presented, the Sixth Circuit clarified the appropriate inquiry as follows: The defendants “devote a great deal of energy to disputing the correctness of the Yard-Man inference. El Paso even suggests that this panel should overrule Yard-Man. These concerns are significantly overstated. El Paso and CNH America misinterpret the term ‘inference’ and confuse it with a legal presumption. Under Yard-Man we may infer an intent to vest from the context and already sufficient evidence of such intent. Absent such other evidence, we do not start our analysis presuming anything. If Yard-Man required a presumption, the burden of rebutting that presumption would fall on the defendants. However, there is no legal presumption that benefits vest and that the burden of proof rests on plaintiffs. This Court has never inferred an intent to vest benefits in the absence of either explicit contractual language or extrinsic evidence indicating such an intent. Rather, the inference functions more to provide a contextual understanding about the nature of labor-management negotiations over retirement benefits. That is, because retirement health care benefits are not mandatory or required to be included in an agreement, and because they are ‘typically understood as a form of delayed compensation or reward for past services’ it is unlikely that they would be ‘left to the contingencies of future negotiations.’ When other contextual factors so indicate, Yard-Man simply provides another inference of intent. All that Yard-Man and subsequent cases instruct is that the Court should apply ordinary principles of contract interpretation.” Yolton v. El Paso Tenn. Pipeline Co., 435 F.3d 571 (6th Cir. 2006).