As long as you instruct the IRA custodian to make a "return of excess contribution" by the extended 2018 due date of Oct. 15, 2019 then the IRA custodian will isssue a 2019 1099-R with a code JP in box 7 and the returned amount in box 1 with any earnings in box 2a. That will avoid the 2018 penalty.
That must be reported on an amended 2018 tax return if you already filed. There is no reason whatsoever to amend before you receive the 1099-R in Jan of 2020. The only point of submitting a "dummy" 10999-R in advance of the actual 1099-R is to report it on an original tax return to *avoid* having to amend at all. Since you already filed there is no benefit to amend before receiving the actual 1099-R and if it is different than you think it will be then you would have to amend the amend which is a very messy procedure.
Just have the excess removed before Oct 15 and amend next year when the 1099-R is in hand.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
