Every radio common carrier shall have the right, and may be so required, to charge annually as an operating expense a reasonable sum for depreciation and credit the same to a reserve account for such purpose, which reserve account shall be charged with plant retirements, but if the reserve thus created shall at any time in the judgment of the Commission be excessive, the Commission after due hearing shall make such order as will result in credits to such reserve thereafter conforming to actual facts and conditions as ascertained by the Commission; provided, that the Commission shall have the right and power to control or limit such depreciation reserve; provided, further, that nothing in this section shall be construed to be in conflict with or in violation of the provisions of the Communications Act of Congress of 1934, as amended (U.S.C.A. Title 47, Sections 151 through 609), nor shall they be construed to be in conflict with any lawful order of the Federal Communications Commission issued pursuant to the authority invested in it by such act of Congress.