Don't they do that every year pretty much? They see that the tickets for Halloween weekend are slow so they add in the dates to pick up the amount of people in the park.
Uni reallty needs to put in a year round haunt as well, but thats another argument for a different thread.
On another note, I was hoping that they would have a preview to next years event sometime this week like they did last year.. I guess that ain't happening.