Advance tax installment thresholds revised; shortfall attracts simple interest and modified exceptions under new amendment. The amendment to Section 234C, effective 1 June 2016, revises advance tax installment benchmarks and prescribes simple interest on shortfalls: non presumptive taxpayers face staged installment requirements with interest on periodic shortfalls subject to a moderating proviso for minimum early payments, while presumptive taxpayers under the presumptive taxation regime are liable to simple interest only for any final shortfall. The proviso is expanded to include income from business or profession arising for the first time and related cross reference adjustments.