grabiner wrote:You don't even file Form 1040-ES with the IRS.
Oh yes you do! How else would the IRS know where to credit the deposit? You are required to send the 1040-ES voucher with your check unless you use online payments.
But you don't file the calculations, just the voucher; the IRS doesn't care how you decided that you would pay $1000 of estimated tax. (Similarly, you file a W-4 claiming your withholding allowances, but you don't file the worksheet in which you determined how many allowances you were entitled to claim unless the IRS questions your withholding.)
In fact, I had several years when I had a taxable scholarship in which I didn't bother to fill out the 1040-ES to estimate my tax; I paid estimated tax equal to the tax owed in the previous year, knowing that thus would be enough to avoid a penalty, and that I had enough cash in my bank account to pay the tax bill in April.