I don't recall a faq with that name, maybe someone else will.
Perhaps your friend would like to join us and we could offer some individual advice based on her situation?
Depending on her current routine OT could be caused from LO being kept awake too long or from too much stimulation during (what would be) a reasonable length of A time. However OT can also because by the A time being too short and LO settles down to a nap but only sleeps 1 cycle before waking, LO is not tired enough to transition to another cycle and is impossible to put back to sleep. The short UT nap leads to less sleep than LO needs so over the course of the day OT builds up...and can continue to build over days.