The President shall, by order, determine the grants-in-aid of the revenues of the States of Assam, Manipur, Meghalaya and Tripura and the share of each such State in the Union duties of excise, estate duty and taxes on income and for that purpose amend thereby the relevant provisions of the Union Duties of Excise (Distribution) Act, 1962 (3 of 1962), the Additional Duties of Excise (Goods of Special Importance) Act, 1957 (58 of 1957), the Estate Duty (Distribution) Act, 1962 (9 of 1962) and the Constitution (Distribution of Revenues) Order, 1969 in such manner as he thinks fit.