(1) Where an instrument is chargeable with ad valorem respect of any money expressed in any currency other that of India, such duty shall be calculated on the value of such money in the currency of India according to the current rate of exchange on the day of date of the instrument.

(2) The rate of exchange prescribed by the Central Government under subsection (2) of section 20 of the Indian Stamp Act, 1889 (Central Act II of 1889) shall be deemed to be the current rate of exchange for the conversion of any foreign currency for the purpose of calculating the duty under subsection(1).