Rounding of tax amounts: fractional paise are adjusted to the nearest rupee, affecting GST liabilities and refunds. Section 170 requires that tax, interest, penalty, fine, refunds and any other sums payable or due be rounded to the nearest rupee; fractional paise below the half-rupee threshold are ignored while fractional paise at or above that threshold are increased to the next rupee, applying equally to amounts payable and refundable under the Act.