(a) Except as hereinafter provided, each employee of the Department of Veterans Affairs heretofore or hereafter appointed to, or lawfully filling, any position designated in paragraph (b) of this section is hereby delegated authority, within the limitations and conditions prescribed by law, to exercise the powers and functions of the Secretary with respect to the guaranty or insurance of loans and the rights and liabilities arising therefrom, including but not limited to the adjudication and allowance