(2) If any return, claim, statement, notice, application, or other document required to be filed, or any payment required to be made, within a prescribed period or on or before a prescribed date under authority of any provision of this article is, after such period or such date, delivered by United States mail to the tax commission, bureau, office, officer or person with which or with whom such document is required to be filed, or to which or to whom such payment is required to be made, the date of the United States postmark stamped on the envelope shall be deemed to be the date of delivery. This subdivision shall apply only if the postmark date falls within the prescribed period or on or before the prescribed date for the filing of such document, or for making the payment, including any extension granted for such filing or payment, and only if such document or payment was deposited in the mail, postage prepaid, properly addressed to the tax commission, bureau, office, officer or person with which or with whom the document is required to be filed or to which or to whom such payment is required to be made. If any document is sent by United States registered mail, such registration shall be prima facie evidence that such document was delivered to the tax commission, bureau, office, officer or person to which or to whom addressed. To the extent that the tax commission shall prescribe by regulation, certified mail may be used in lieu of registered mail under this section. This subdivision shall apply in the case of postmarks not made by the United States Post Office only if and to the extent provided by regulation of the tax commission.

(3) When the last day prescribed under authority of this article (including any extension of time) for performing any act falls on Saturday, Sunday or a legal holiday in the state of New York, the performance of such act shall be considered timely if it is performed on the next succeeding day which is not a Saturday, Sunday or a legal holiday.

(4)(A) Any reference in paragraph two of this subdivision to the United States mail shall be treated as including a reference to any delivery service designated by the secretary of the treasury of the United States pursuant to section seventy-five hundred two of the internal revenue code and any reference in paragraph two of this subdivision to a postmark by the United States mail shall be treated as including a reference to any date recorded or marked in the manner described in section seventy-five hundred two of the internal revenue code by a designated delivery service. If the commissioner finds that any delivery service designated by such secretary is inadequate for the needs of the state, the commissioner may withdraw such designation for purposes of this article. The commissioner may also designate additional delivery services meeting the criteria of section seventy-five hundred two of the internal revenue code for purposes of this article, or may withdraw any such designation if he finds that a delivery service so designated is inadequate for the needs of the state. Any reference in paragraph two of this subdivision to the United States mail shall be treated as including a reference to any delivery service designated by the commissioner and any reference in paragraph two of this subdivision to a postmark by the United States mail shall be treated as including a reference to any date recorded or marked in the manner described in section seventy-five hundred two of the internal revenue code by a delivery service designated by the commissioner.

(B) Any equivalent of registered or certified mail designated by the United States secretary of the treasury, or as may be designated by the commissioner pursuant to the same criteria used by such secretary for such designations pursuant to section seventy-five hundred two of the internal revenue code, shall be included within the meaning of registered or certified mail as used in paragraph two of this subdivision. If the commissioner finds that any equivalent of registered or certified mail designated by such secretary or the commissioner is inadequate for the needs of the state, the commissioner may withdraw such designation for purposes of this article.

(b) The provisions of the civil practice law and rules or any other law relative to limitations of time for the enforcement of a civil remedy shall not apply to any proceeding or action taken by the state or the tax commission to levy, appraise, assess, determine or enforce the collection of any tax or penalty provided by this article. However, except in the case of a willfully false or fraudulent return with intent to evade the tax no assessment of additional tax shall be made after the expiration of more than three years from the date of the filing of a return; provided, however, that where no return has been filed as provided by law, the tax may be assessed at any time. Where a purchaser furnishes a vendor with a false or fraudulent certificate of resale or other exemption certificate or other document with intent to evade the tax, the tax may be assessed against such purchaser at any time. For purposes of this subdivision, a return filed before the last day prescribed by law or regulation for the filing thereof or before the last day of any extension of time for the filing thereof shall be deemed to be filed on such last day. Notwithstanding any other provision of this article, if the time to assess additional tax would otherwise have expired on or before December nineteenth, nineteen hundred sixty-nine, the time to assess such additional tax is hereby extended to and including December twentieth, nineteen hundred sixty-nine, except that it may be further extended by a taxpayer's consent in writing as provided in subdivision (c) hereof.

(c) Where, before the expiration of the period prescribed herein for the assessment of an additional tax, a taxpayer has consented in writing that such period be extended the amount of such additional tax due may be determined at any time within such extended period. The period so extended may be further extended by subsequent consents in writing made before the expiration of the extended period. If a taxpayer has consented in writing to the extension of the period for assessment, the period for filing an application for credit or refund pursuant to section eleven hundred thirty-nine shall not expire prior to six months after the expiration of the period within which an assessment may be made pursuant to the consent to extend the time for assessment of additional tax.

(d) The limitation of time for the assessment of additional tax, shall, after the mailing of a notice of determination, be suspended with respect to the amount of additional tax asserted in such notice until the expiration of the time for filing a petition contesting such notice or, if a timely petition with respect to the amount asserted in such notice has been filed with the division of tax appeals, until the determination of the administrative law judge or the decision of the tax appeals tribunal has become final. A determination of an administrative law judge in the division of tax appeals shall become final in accordance with subdivision four of section two thousand ten of this chapter. A decision of the tax appeals tribunal shall become final upon the expiration of the period specified in paragraph four of subdivision (a) of section eleven hundred thirty-eight of this article for making an application for review if no such application has been duly made within such time, or, if such application has been duly made, upon expiration of the time for all further judicial review, or upon the rendering by the tax appeals tribunal of a decision in accordance with the mandate of the court on review. Notwithstanding the foregoing, for the purpose of making an application for review, the decision of the tax appeals tribunal shall be deemed final on the date the notice of such decision is served as provided in section two thousand sixteen of this chapter.