you're on the right track but not quite.
you will use a 2019 form 5329 showing 864 excess from last year.
then since you put in less than the maximum allowed for you, you can "resolve" the excess by applying 864 .
(all assuming your income is over 3864).
See Form 5329
unfortunately you owe 6% penalty in 2018 for that excess so you will have to amend your 2018 return to add 2018 5329 and pay up.
doing that will produce the numbers you need for your 2019 form 5329.
Got it ?
