(petitioner entered into settlement agreement arising from personal non-physical personal on-the-job injuries; settlement agreement did not indicate that parties intended petitioner to receive settlement proceeds in exchange for settling claim under Iowa Workers' Compensation Act (IWCA); and only included vague reference to workers' compensation claim where agreement conditioned on petitioner settling workers' compensation claim; court determined that such vague reference not sufficient to establish that petitioner paid proceeds in exchange for settling claim under IWCA; petitioner's lawyer also failed to offer any documents relating to petitioner's claims under IWCA; burden of proof is on petitioner to establish exclusion from income for amount to compensate petitioner for personal injuries in accordance with I.R.C. Sec. 104(a) and Treas. Reg. Sec. 104-1(b); petitioner's lawyer also failed to argue either at trial or on briefs that any portion of settlement proceeds related to medical care for petitioner's emotional distress - such amounts are excludible from income in accordance with I.R.C. Sec. 104(a)(2); 20 percent underpayment penalty imposed).