An act amending the act of March 16, 1970 (P. L. 180, No. 69), entitled "An act relating to State taxation; changing the manner of which tentative and annual taxes are to be paid; providing a penalty in certain cases; and making a repealer," further providing for a revision in the method of reporting, for additional tax for understatement, and for the reporting and payment of the tentative corporate net income tax and corporation income tax in installments.