"[The proposed legislation would prohibit] 'plans from seeking recoupment if the first overpayment occurred more than three years before the participant (or beneficiary) is notified in writing about the error,' ... The legislation would also prevent plans from charging fees or interest on the overpayments, and it would also limit the amount that retirement plans can reduce a benefit, so that the amount 'being paid back yearly could not exceed 10% of the amount the person was overpaid.' "