Surcharge payment timing altered for advance tax instalments; deferred payment deadlines and mandatory deduction adjustments apply. Payment timing of surcharge is modified for advance tax instalments: domestic companies have the surcharge on the mid-September instalment payable by mid-November; non-domestic assessees have surcharge on mid-September and mid-December instalments payable by mid-March. Where income-tax is calculable or chargeable under specified provisions, surcharge is payable only when such income-tax is calculated or charged. Persons making payments under the withholding provisions must, after the Act's assent, adjust any deficiency arising from prior deductions due to the increased surcharge rate.