(b) If a tax-free NY area approved pursuant to the provisions of article twenty-one of the economic development law is located within the MCTD, the payroll expense in such tax-free NY area of any employer that is located in such area and accepted into the START-UP NY program shall be exempt from the tax imposed under this article. In addition, the net earnings from self-employment of an individual from a business in such tax-free NY area that is accepted into the START-UP NY program shall be exempt from the tax imposed under this article.