First, glad I read all of this as I had similar questions. Comparing my PDF files from 2020 to 2021, the 2020 form allowed direct deposit (credit) but not a payment (debit) of MO taxes due when electronically filing (you either had to send a check or go to the website) but 2021 it has the option for both debit and credit. I almost made a payment on the website as some of you did but, based on everything I've read here, I feel confident that the payment made as part of the 2021 electronic filing should go through. Thanks to all for the great posts!
As to the question on late payments, my understanding is that as long as you filed electronically before the deadline the payment will be "on time". It is just like if you mail your return... as long as it is postmarked by the due date you are good to go!
