The IRS filed proofs of claim against each of the debtors in this jointly administered case for priority tax claims under 11 U.S.C. § 507(a)(7)(E) and (G) or, in the alternative, as administrative claims for "excise taxes" pursuant to 26 U.S.C. § 4971(a) and (b). The claims were based on debtors' failure to make minimum funding payments to their ERISA-qualified pension plans. Pursuant to § 4971(a), the IRS imposes an immediate 10% first-tier tax, based on accumulated funding deficiency, when an employer fails to make the minimum funding contribution to an ERISA-qualified plan when their annual report is due. If the sponsoring employer does not correct the deficiency, § 4971(b) imposes an additional second-tier tax equal to 100% of the accumulated funding deficiency. The IRS filed amended proofs of claim for the debtors' liability under § 4971(a) and (b), as postpetition administrative priority or, alternatively, as prepetition priority taxes under § 507(a)(7)(E) and (G). In addition to findings based on the specific circumstances related to timing and claim calculations peculiar to this case, the court found that claims for excise taxes under § 4971 are neither excise taxes given priority by § 507(a)(7)(E), nor pecuniary loss penalties related to a governmental claim under § 507(a)(7)(G), rejecting the holding of In re Mansfield Tire & Rubber Co., 942 F.2d 1055 (6th Cir. 1991), cert. denied sub nom, Krugliak v. United States, 112 S. Ct. 1165 (1992). The court also found that penalties under § 4971 do not relate to a tax and, therefore, are also not entitled to administrative priority under 11 U.S.C. § 503(b)(1)(C). The IRS asserted that, since its original proofs of claim included protective language that placed debtors' income tax liability in issue, amended proofs of claim should be permitted to cure the defect in the claims as originally filed. The court held, under the circumstances of this case, that whether the original proofs opened the door for later amendment was subject to different interpretations, and reserved that issue for further evidentiary proceedings. However, the court held that the original proofs did not give the debtor notice of the existence or amount of the 1990 excise tax claims under § 4971. The court concluded that, as the amended proof of claim created a new claim that tripled the amount of the original claim, allowance of the amended claim was not justified.