Notwithstanding anything contained elsewhere in this Act, any dealer eligible under section 40, or section 42 or section 43, to defer the tax payable according to his returns referred to under sub-section (2) of section 30 or the tax due from him according to a notice issued under section 47, shall have an option to make payment before the expiry of the period for which he is eligible to defer the payment of such tax on the basis of a discount formula, and in such manner, as may be prescribed.