(1)Notwithstanding anything contained in section 4 or 6 or any other enactment, unless it is proved that the duty chargeable under this Act has been paid,-(a)on the principal or original instrument, as the case may be, or(b)in accordance with the provisions of this section, the duty chargeable on an instrument of sale, mortgage, or settlement, other than a principal instrument or on a counterpart, duplicate or copy of any instrument shall, if the principal or original instrument would, when received in this State have been chargeable under this Act with a higher rate of duty, be the duty with which the principal or original instrument would been chargeable under section 19.
