I filed with the penalty written into my 1040 box 38. I don't get a refund (I underpaid, after all). So the direct debit for my tax bill will be coming out of my checking account next week.
I amended a return last year when some banks sent me forms very late that should have been in the original return, so I'm familiar with the process when it's a change I need to make. But when it's a change that TurboTax may need to make based on an updated formula for underpayment, I'm just wondering what to expect.
