The TEFRA partnership audit rules are confusing. The "large corporate underpayment" interest rules are confusing. When they intersect, it's even worse. That happened in the General Mills decision last year, in which the Federal Circuit rules that the plaintiff's refund suit was filed too late under the applicable TEFRA provision. Part 3 looks at the hot interest issue, which the court didn't address as the case was dismissed for lack of jurisdiction. But it's a novel issue that's worth looking at.