Where an order giving rise to a refund is the subjectmatter of an appeal or further proceeding or where any other proceeding under this Act is pending, and the authority competent to grant such refund is of the opinion that the grant of the refund is likely to adversely affect the revenue, such authority (not being the Commissioner) with the previous approval of the Commissioner may withhold the refund till such time as is deemed fit:
     Provided that the Commissioner may, on application or otherwise, order for release of such refund if he is of the opinion that the situation does not require such action on the part of the prescribed authority.