Unless entitled to a higher grade under another provision of law, a reserve commissioned officer, other than a commissioned warrant officer, who is transferred to the Retired Reserve is entitled to be placed on the retired list established by section 12774 (a) of this title in the highest grade in which he served satisfactorily, as determined by the Secretary concerned and in accordance with section 1370 (d), in the armed force in which he is serving on the date of transfer.