Rounding off of tax amounts: totals rounded to nearest standard unit, with upward adjustment when the final digit is halfway or more. The statute directs that computed total income or any amount payable or refundable be rounded to the nearest multiple of ten ignoring paise; if not a multiple of ten the amount is increased to the next higher multiple when the last digit is five or more and reduced to the next lower multiple when the last digit is less than five, and the rounded figure is deemed to be the operative total income or amount payable or refundable.