SECTION 1. A new sub-paragraph to be known as sub- paragraph (F) is hereby inserted at the end of Section 28(b)(8) of the National Internal Revenue Code, as amended, which shall read as follows:
"(F) 13th month pay and other benefits.
"(i) Benefits received by officials and employees of the national and local governments pursuant to Republic Act No. 6686;
"(ii) Benefits received by employees pursuant to Presidential Decree No. 851, as amended by Memorandum Order No. 28, dated August 13, 1986;
"(iii) Benefits received by officials and employees not covered by Presidential Decree No. 851, as amended; and
"(iv) Other benefits such as productivity incentives and Christmas bonus in an amount not exceeding Twelve thousand pesos (P12,000) which shall be integrated in the 13th month pay solely for purposes of this Act.
"Provided, however, That the exclusion shall only apply to the first Thirty thousand pesos (P30,000)."