20.9.2.0.3. Where a person has purchased movable property before 1 January 1991 and returns it to the vendor after 31 December 1990 and before 1 February 1991 in exchange for other movable property and where the sale price of the other property exceeds that of the returned property, the person shall pay the tax provided for in this chapter on the excess only and is not entitled to a reimbursement of the tax paid by him in respect of the returned property, if any.