Whenever the hearing is conducted by an administrative law judge, at the conclusion of the hearing he shall submit a recommended decision to the Commission, which shall include a statement of findings and conclusions, as well as the reasons therefor. The applicant, the Secretary and others to whom notice has been sent pursuant to § 4.7 may file with the Commission, within 10 days after having been furnished a copy of the recommended decision, exceptions thereto and reasons in support thereof. The Commission may order the taking of additional evidence and may request the applicant and others to appear before it. The Commission may invite oral argument before it on such questions as it desires.