A question about Dick Cheney's tax return

The Veep's total tax liability was $394,000 of which $103,000 was paid with the filing of the return today. Normally such a large final payment would incur a penalty. So is it included in that payment today -- and if so, is Dick steamed at his accountant? Or do Dick's many interests get him under "special rules for farmers and fishermen"?

UPDATE: Reader LR draws our attention to the Veep's 2003 tax return, where he had made about the same payments prior to filing as this year. This may bring him under one of the exceptions to the penalty rule. Also, check out Dick's ability to earn $627,000 in non-taxable interest income! And here's the 2004 return, without the additional pages to explain if there is a penalty. Any chance of seeing the attached statements?

FURTHER UPDATE APRIL 18: The Washington Post is also curious about the witholding:

I [Dan Froomkin] have one question: Apparently, the Cheneys under-withheld over the course of the year to the tune of $102,663. Isn't that against the rules? Tax experts, let me know: [e-mail in article] ... to which Cheney's accountant responds the same way as reader LR above].