Any person whose land or entry, prior to August 13, 1914, became subject to the terms and conditions of the reclamation law shall pay the construction charge, or the portion of the construction charge remaining unpaid, in twenty annual installments, the first of which shall become due and payable on December 1 of the year in which the public notice affecting his land is issued, and subsequent installments on December 1 of each year thereafter. The first four of such installments shall each be 2 per centum, the next two installments shall each be 4 per centum, and the next fourteen each 6 per centum of the total construction charge, or the portion of the construction charge unpaid at the beginning of such installments.

Any person whose land or entry prior to August 13, 1914, became subject to the reclamation law, who desires to secure the benefits of the extension of the period of payments provided by sections 373, 414, 418, 435 to 437, 440, 443, 464, 465, 469, 471, 472, 475, 477 to 481, 492, 493, 494 to 497 and 499 of this title, shall, within six months after the issuance of the first public notice hereunder affecting his land or entry, notify the Secretary of the Interior, in the manner to be prescribed by said Secretary, of his acceptance of all the terms and conditions of such sections, and thereafter his lands or entry shall be subject to all of the provisions of such sections: Provided, That upon sufficient showing the Secretary of the Interior may, in his discretion, permit notice of acceptance of all the terms and conditions of such sections to be filed at any time after the time limit hereinbefore fixed for filing such acceptance shall have expired, conditioned, however, that where the applicant for such acceptance is in arrears on construction charges, he shall at the time of acceptance pay such installments of the construction charge as he would have been required to pay had he accepted the benefits of such sections within the time limit hereinabove fixed, plus the penalties that would have accrued had he so accepted, and such applicant shall thereafter be upon the same status that he would have been had he accepted the provisions of such sections within the time limit hereinabove fixed, and thereafter the lands or entry of any such persons so filing such notice of acceptance shall be subject to all the provisions of such sections.