The Registrar may, on such terms as he thinks just, at any time, whether before or after acceptance of an application for registration under section 18, permit the correction of any error in or in connection with the application or permit an amendment of the application:
     Provided that if an amendment is made to a single application referred to in sub-section (2) of section 18 involving division of such application into two or more applications, the date of making of the initial application shall be deemed to be the date of making of the divided applications so divided.