Where there are two or more timely applicants for a farm unit on a particular project or division thereof under the provisions of this subchapter, one or more of whom is an ex-serviceman who would be entitled under the applicable statutes to a preference in making entry of farm units on such project or division, the ex-serviceman, or one of them, shall have a preference in making such exchange. Any timely applicant for an exchange under the provisions of this subchapter shall be entitled to preference over any other applicant for a farm unit on the same project or division thereof.