Sec. 505. Section 1780(a) of title 38, United States Code, is amended— (1) by striking out at the end of clause (1) “or”; (2) by striking out the period at the end of clause (2) and inserting in lieu thereof a semicolon; and (3) by inserting immediately after clause (2) the following new clauses: (3) to any eligible veteran or person for auditing a course; (4) to any eligible veteran or person for a course for which the grade assigned is not used in computing the requirements for graduation including a course from which the student withdraws unless the Administrator finds there are mitigating circumstances; or (5) to any eligible veteran or person for pursuit of a program of education exclusively by correspondence as authorized under section 1786 of this title or for the pursuit of a correspondence portion of a combination correspondence-residence course leading to a vocational objective where the normal period of time required to complete such correspondence course or portion is less the 6 months. A certification as to the normal period of time required to complete the course must be made to the Administrator by the educational institution.”.