(1) The State Government, after giving by notification not less than fourteen days notice of its intention so to do, may, by like notification, with prospective or retrospective effect, add to, amend, or alter, any Schedule to his Act :

PROVIDED that no entry or part thereof in respect of any goods specified in Schedule I shall be omitted from that Schedule :

PROVIDED FURTHER that no Schedule, other than Schedule IV, shall be so amended by way of addition or alteration as to enhance the rate of tax on sale of any goods to more than twenty five per centum of the taxable turnover of sales of such goods.

(2) Where any goods specified in Schedule, other than Schedule IV, is transferred to Schedule IV, and where a dealer, who has purchased such goods before the date of such transfer to Schedule IV against the declaration referred to in the first proviso to sub-section (2) of section 17 issued or to be issued by him or against the declaration referred to in the second proviso to clause (gg) of sub-section (1) of section 17 issued or to be issued to him, sells such goods on or after the aforesaid date, the tax payable by him on his taxable turnover of sales of such goods shall, notwithstanding the rate of tax fixed under section 18, be levied-

(a) at the rate fixed in clause (a), clause (b) or clause (d), clause (e), clause (f), clause (g) or clause (h), as the case may be, of sub-section (1) of section 17 which would have been applicable to sales of such goods on the date immediately preceding the date of such transfer to Schedule IV, or

(b) at the rate fixed in clause (b), clause (c), clause (d) or clause (e) of sub-section (2), sub-section 2A of section 17 in respect of sales referred to therein,

as the case may be.

(3) Where any goods specified in Schedule, other than Schedule IV, is transferred to Schedule VIIIA, and where a dealer, who has purchased such goods before the date of such transfer to Schedule VIIIA against the declaration referred to in the first proviso to sub-section (2) of section 17 furnished or to be furnished by him, sells such goods on or after the date of such transfer, the tax payable by him on his taxable turnover of sales of such goods shall, notwithstanding the rate of tax fixed under clause (gg) of sub-section (1), or sub-section (2A), of section 17, be levied-

(a) at the rate fixed in clause (b), clause (d), clause (e), clause (f), clause (g), or clause (h), as the case may be, of sub-section (1) of section 17, or

(b) at the rate fixed in clause (b), clause (c), clause (d), or clause (e), of sub-section (2) of section 17 in respect of sales referred to therein,

as the case may be,

as if the goods sold after the date of such transfer were, notwithstanding the transfer of such goods to Schedule VIIIA, specified in such Schedule as is referred to in clause (b), clause (d), clause (e), clause (f), clause (g), or clause (h), as the case may be, of sub-section (1) of section 17.

(4) Where any goods specified in column (2) of Schedule VIIIA has been purchased by a dealer in West Bengal before the date of any amendment in rate under column (4) of the said Schedule is made on payment of tax at the rate fixed under column (3) of the said Schedule from a registered dealer in West Bengal and such purchasing dealer makes sales of the goods so purchased on or after the date on which any amendment in the rate of tax under column (4) of the said Schedule is made, the tax payable by such dealer shall be levied-

(a) at the rate fixed under column (4) of the said Schedule, as if the rate of tax fixed thereunder remained unaltered notwithstanding the amendment made therein, or

(b) at the rate specified in clause (b), clause (c), clause (d), or clause (e), of sub-section (2) of section 17 in respect of sales referred to therein,

as the case may be.