Hilton's reservation system now shows agents the per night price - having taken into account any free nights before displaying the point price for the room. So if a room costs 20k points and you have a 5 night stay, the room will show as 16k points per night for five nights right off the bat. The only way to (usually) see this is to reduce the stay to four nights and notice that a four night stay would be 80k points (i.e. the same total as a five night stay).