Sometimes tweaking your trip dates by just a few days can have a significant impact as well. Weekend rates are higher, for example. I see that value season goes from July 19 to October 1, so there shouldn't be a season change in August....but other times - a few days can mean a big difference. At BC a st. room beofre July 19 is $380, after it's $335 (not incl. taxes).
Another thing that can make a big differnce is making sure the prices you're seeing include the tax. At most resorts it's 12.5%, at the All Stars it's 13% (They are in a different county from allthe other resorts).