In Dysart v. United States, 169 Ct.Cl. 276, 340 F.2d 624 (1965), the taxpayer sought a refund of an improperly paid penalty for underestimation of income for the year involved. Dysart, 340 F.2d at 626-27. The government sought to offset an alleged tax deficiency for the same year, the time for assessing which had expired. Id. at 627. The court denied the taxpayer's motion to strike the offset. It stated: In a refund action, the taxpayer cannot recover unless he has overpaid his tax. It is not enough that he can prevail on the particular items on which he sues, for he may have underpaid with respect to other components entering into that tax. Only if the overall balance moves his way can he recover. His entire tax liability under the particular tax return is therefore open for redetermination. The setoff is one mechanism by which the government alleges that, looking at the particular tax as a whole, the taxpayer has not in fact overpaid his tax. Id. at 628. The court referred to "the essential principle that a taxpayer suing for a refund of a tax for a particular year must show that, in actuality, he overpaid that tax." Id. at 629-30. The court also ruled that "the government's right to raise a setoff is not subject to equitable considerations as taxpayers contend." Id. at 627.