Your 90-day window to take the Exam only allows you to take the Exam once. If you fail, you have to reapply, but the second time (as long as its within a year of your first application), they won't need the paperwork (transcript, course descriptions) again and they'll pretty much automatically send you a second 90-day window to sit for the Exam (about two weeks from the receipt of your second application, no matter how long it took them to decide on your first application). So, you may be "lucky" enough to take the Exam twice within 90 days, but it's based on two separate windows.
Mark Dighton, Admin. Director, PLI's Patent Bar Review