If I mail my payment on the due date do I have to pay a penalty?

NYS RPTL 925 provides as follows: “Payment of taxes by mail, when enclosed in a postpaid wrapper (envelope) properly addressed to the appropriate collecting officer and is deposited in a post office or official depository under the exclusive care and custody of the United States Post Office shall, upon delivery, b deemed to have been made to such officer on the date of the United States Postmark on such wrapper. The provisions of this section shall not apply in the case of postmarks not made by the United States Post Office. A postage meter postmark is not a postmark made by the United States Post Office and, therefore, is not within the provisions of Real Property Tax Law 925. Payments cannot be deemed timely because of a postage meter postmark date on an envelope containing a tax payment (Op. New York State Com. 68-626).