@Raiden2a
Simplest way is to pay the extra 1/3 as another estimated payment with your tax return when you file. Then request on the return that the excess payment not be refunded but carried over to the following year. That way the IRS has it paid as 1/3, 1/3, 1/3 and you are able to pay it all a year early. Although why anyone would want to pay a tax before it is due, I don't quite understand....
