Think long and hard about this before making a repayment. There are many potential factors that could influence whether it is a good/bad decision. Just off the top of my head, some factors might be: (a) whether the maximum allowable benefit is/was reached (or even close), (b) whether the plan's benefit formula has changed since you left, (c) if the plan is not frozen now, what is the likelihood of such occurrence, etc. Other actuaries may contribute additional concerns.