On the expiration of the period for which the coupons attached to a stock certificate to bearer have been issued under this Act, the certificate may be exchanged for another certificate with coupons for a further period: Provided, that the certificate issued in exchange, if the stamp duty has not been compounded, shall be duly stamped, but in such case the Commissioners of Inland Revenue shall, on production to them of both certificates duly stamped, and subject to such regulations as they may from time to time make, grant allowance for the stamp on the former certificate.