The proposed ban comes as more states are restricting colleges and universities from withholding transcripts when a student owes money to the institution. The planned federal ban would only apply in some cases. A proposed ban to limit when colleges and universities can withhold a student’s transcript could help thousands of students, if not more than a million, access their credits and resume their college education, experts and advocates say. “It’s a modest but important step,” said Martin Kurzweil, vice president of educational transformation at Ithaka S+R, a research and consulting shop that has reported over the last several years on how transcript withholding affects millions of students.