OH, yes. And don't think they won't try. I received my lump sum and thought it was what it should be. Called some colleagues and we were all in the same ballpark. I called Fidelity and they confirmed the payout.
A year later, I was reading an article in a financial/ business magazine about companies screwing employees re: pensions and payouts with a link to a website. Went to it and ran the calculation. Guess what? I got screwed. Called Pfizer and Fidelity, and they swore on a bible and shook hands with God that it was correct. I hung up the phone, called a lawyer friend who requested a full disclosure of the calculations. Expecting the same one they sent originally.
Three weeks went by and nothing. The next week, a check for $95,678.37 arrived in the mail with a letter stating that after an audit, they had miscalculated my pension lump sum payout.
Was it the "audit", or did I catch them in a lie?