Section 84. Extension of period of limitation in certain cases

An appellate authority may admit any appeal or permit the filling of a memorandum of cross objections under section 73 and the Tribunal may admit an application under section 75 or under section 78 after the period of limitation laid down in the said sections, if the appellant or the applicant satisfies the appellate authority or the Tribunal, as the case may be, that he had sufficient cause for not preferring the appeal or filing a memorandum of cross objections or making the application, within such period.