...The decision of the Secretary or duly authorized representative for the resolution of such disputes shall be final and conclusive, unless determined by...supported by substantial evidence. In connection with any proceeding under this Section, the Owner shall be afforded an opportunity to be heard and to offer...

...date of receipt of such copy, the Contractor mails or otherwise furnishes to the Contracting Officer i written appeal addressed to the Secretary. The decision...Contractor shall be afforded an opportunity to be heard and to offer evidence in support of its appeal. Pending final decision of a dispute hereunder,...