regarding what happens when one books a hotel thru PTS

is the credit applied before even the charge goes thru? for example what happens if the hotel booking isnt a prepaid one, where the charge isnt until later? does PTS charge the non prepaid bookings right away + give $200 credit, or give $200 right away, charge later, or do both of them later when checking in & paying?

i found a booking on SPG.com thats a prepaid price, for 30% less than PTS quote. oddly the quote isnt available on expedia either (maybe thats why PTS couldnt see that rate). thus i was wondering what alternatives i had.

edit: sorry forgot to say its for Amex Canada