No that's right. If you made the 4th quarter state estimated payment in January then you can not deduct it on a federal return for 2018. Only state payments actually made in 2018 are a deduction. So a January 2019 state payment will go on next year's 2019 federal return as a deduction. You have to enter the dates you actually made the payments.
Now if you made a 2017 4th quarter state payment a year ago in January 2018 you can also deduct that on your 2018 federal return.
So again, the federal state and local deductions worksheet should NOT include a Jan 2019 state payment. You have to remember to enter it into next years 2019 return. If you wanted it to be a 2018 Deduction you needed to pay it IN 2018.
