May students whose conduct is identical be given different sanctions?
Yes.
A board may find that two or more students have committed the same policy violation, but may use its discretion to determine different punishments for the students. E.g., in In re McGee, 16 DE App. Dec. 324 (1999), one student was expelled and another received a lesser punishment for the same violation. In determining appropriate sanctions (but not in determining whether a violation occurred), the board may consider a student's prior disciplinary record and any extenuating circumstances.