A casual taxable person or a non-resident taxable person shall, at the time of submission of application for registration under sub-section (1) of section 25, make an advance deposit of tax in an amount equivalent to the estimated tax liability of such person for the period for which the registration is sought:
Provided that where any extension of time is sought under sub-section (1), such taxable person shall deposit an additional amount of tax equivalent to the estimated tax liability of such person for the period for which the extension is sought.