The problem here is that it is the PLAN'S responsibility to maintain the records - NOT the participants.... Every controversy requires a cost/benefit analysis to determine what is the most efficient outcome. I'm not saying just make an offer. I'm saying figure out what are the reasonable outcomes, what are the risks, and make a business decision....
Whether paying someone off sets a bad precedent or not is irrelevant (as is your snarky attitude). Plan has an OBLIGATION to maintain records. Plan did not. Plan may suffer consequences. The question is the best course of action to resolve it. There are three - find or recreate the records, settle the matter, or stick your head in the sand (or elsewhere) and wait for Schlicter {or another attorney) to come a calling....