(4)Where the terms and conditions of a licence have been settled by the Controller, the licensee may, at any time after he has worked the invention on a commercial scale for a period of not less than twelve months, make an application to the Controller for the revision of the terms and conditions on the ground that the terms and conditions settled have proved to be more onerous than originally expected and that in consequence thereof the licensee is unable to work the invention except at a loss:Provided that no such application shall be entertained a second time.
