(1) Where a dealer makes a sale of goods specified in Part B of Schedule IV, bitumen, Liquefied Petroleum Gas (LPG), propane, or butane,-
Provided that the claim for such deduction shall not be allowed unless he produces,-
Provided that the claim for such deduction shall not be allowed unless the selling dealer furnishes, on demand, a declaration in the form appended to this sub-rule, duly filled in and signed by the purchasing dealer or by a person authorised for this purpose :
Provided further that no such claim for deduction shall be allowed if a single declaration covers sales made during a period exceeding one month.