" For purposes of figuring the underpayment penalty, you may elect to treat the tax withheld as paid when it was actually withheld. " what does this mean?

[ibanlopez234]

What does this mean?

[DavidD66]

This is referring to tax withholding such as the tax withheld from your paycheck.  The IRS treats (payroll) tax withholding as if it occurred ratably over the entire year (i.e. equal amounts each quarter, even if all of the withholding occurred in the fourth quarter.  Under certain circumstances, you may want to treat the tax withheld as paid when it was actually withheld.  For instance, if you had a large capital gain, and a large amount of tax withheld, all in the first quarter, you might want to make that election.  For the majority of taxpayers, this is not relevant.  

[fanfare]

it means the form is very complex, if you try to fill in using this option you'll see.

I gave up. and resigned myself to paying the penalty amount shown.