(a) An erroneous refund shall be considered an underpayment of tax on the date such refund was made, and a notice of proposed assessment under § 521(c) of this title with respect to such refund may be mailed to the taxpayer at any time within the later of:
(1) Two years from the making of such refund; or
(2) The limitation period provided by § 531 of this title.
(b) As to any part of an erroneous refund that was induced by fraud or by the intentional misrepresentation of a material fact, a notice of proposed assessment under § 521(c) of this title with respect to such refund may be mailed to the taxpayer at any time.