Collections
Interest is charged on tax amounts due each month from the due date of the tax return. Additional interest is added to the account balance on the first day of a new month. The notice is showing you the amount due through the end of the current month and the amount that will be due as of the first day of the next month. While additional interest may be added to the balance, it does not change the time you have to respond to the notice.
We use the postmark date on the envelope of your payment. If the payment is postmarked by the last day of the month, the account will not accrue additional interest.