I had to take provera 3 times over the last few months, here was my experience each round:
Round 1: Started drinking it on CD43, Had light spotting during the 10 days, it stopped at around the 10th day, AF started then 6 or 7 days later.
Round 2: Started drinking it around CD26, no spotting whatsoever while on Provera, spotting started 5 days after the last pil and AF started 8 days after the last pil
Round 3: Started drinking it around CD24, No spotting while taking it, Spotting started 5 days after the last pil and AF only arrived 10 days after the last pil.
Oh, and don't stop taking it. Tkae it the full 10 days..
Hope this helps.