It may be right - what type of room is he quoting? That would be the biggest thing. Also, how many people? If there are more than 2 adults in the room, you are charged for the extra adults.
For two nights (12/14 and 12/15) WDW website is showing the following -
CR - Garden Wing $609 plus tax, etc.
Tower (park view) $924 plus tax, etc.
AK - Standard view $507 plus tax, etc.
Club level $755 plus tax, etc.
You can see that there is a big difference in price depending on the type of room you select. There are also many other types of rooms, I just choose these two as an example.
BTW - we will be at WDW 12/4 - 12/11!