His payment for the amount due on the first audit was postmarked by the due date but arrived after the due date since he sent the payment via registered mail.
Now NY State is going after him for missed payment plus interest.
He also mentions in the video that he was overpaying his taxes because his accounting software wasn't backing out refunded purchases. This was a low four figure amount but he decided he didn't want to file an amended tax return to recoup the money (I assume because his CPA would do the work and the CPA's costs would eat into the money returned).
Now NY State is going after him for missed payment plus interest.
see https://www.youtube.com/watch?v=OXvuOD1D0gM