I happened to see the following information. Is it true? http://www.upenn.edu/oip/iss/visa/f1/opt.html
You may be entitled to up to 12 months of optional practical training per
educational level. If a student begins a new academic program at a higher
level, the student is eligible for another 12 months of OPT.
Remember, if you return to study at a higher education level, you will be
eligible for another 12 month period of OPT. http://www.asu.edu/studentaffairs/ed/iso/opt.htm
Can I do a second OP