Yes, you will be able to enter it as an estimated tax payment in TurboTax for 2018.
I told you earlier that you could not deduct it for 2018 because you said it was an additional payment for 2017. If the IRS had recorded it as a payment of 2017 tax, you would not be able to deduct it on your 2018 tax return. But now that you know the IRS has recorded it as an estimated tax payment for 2018, you will be able to enter that payment in TurboTax and it will be applied to your 2018 tax.
It doesn't matter how it got to be recorded as a 2018 estimated tax payment. If that's what's in the IRS records, that's what you will enter on your 2018 tax return. As VolvoGirl said, you have to remember to enter it yourself. You won't get any form showing it, and the only way for TurboTax to know about it is for you to enter it.
