(4)Where, before the date of determination of total income under section 270(1) or completion of a regular assessment, tax is paid by the assessee under section 266 or otherwise,—(a)interest shall be calculated as per the foregoing provisions of this section up to the date on which the tax is so paid, and reduced by the interest, if any, paid under section 266 towards the interest chargeable under this section;(b)thereafter, interest shall be calculated at the rate aforesaid on the amount by which the tax so paid together with the advance tax paid falls short of the assessed tax.
