Uniform accounting year and redesigned tax authorities reshape advance tax obligations and mutual fund withholding rules. The Act adopts the financial year as the uniform accounting year, redesignates and consolidates tax authorities and their jurisdiction, redefines the Assessing Officer, and vests the Board with power to assign and delegate functions; it also overhauls advance tax by including all current income for instalment-based payments without filing formal estimates, prescribes computation and instalment rules, and introduces non-deduction and exemption rules for mutual funds established by public sector banks or public financial institutions, with transitional 'removal of difficulties' powers for the Central Government.