As per my knowledge (through 2 articles on Google) time for COMEDK on 13th May is 10 AM to 1PM. There is no choice of a slot for ourselves. And appearing for IPUCET at 2 PM doesn't seem realistic, considering that the centres for the two of them may be far, or the traffic jams, or simply the hectic schedule that would exhaust the students, spoiling the second exam consequently. I don't think a student will be able to give a shot to both exams...