Also, I've been seeing more inaccuracies in box office representations everywhere. Jimmy Kimmel repeatedly referred to Brett Rattner as a billion dollar director, when in fact Brett Rattner had grossed a little less than 850 million dollars domestically prior to Rush Hour 3 coming out which was when Brett Rattner was touring the promotional circuit. Peter Bart and Peter Guber also incorrectly classified Rattner as a billion dollar director on Sunday Morning Shootout. They might have been referring to his international take but I doubt that's the case as that would mean that the number of billion dollar directors would expand to people whose commercial instincts are not that impressive. Guber and Bart also cited Rush Hour as a billion dollar franchise internationally, when Rush Hour 1 and Rush Hour 2 both made less than $600 billion.
There was also an article in Variety I read here: http://www.variety.com/article/VR1117970302.html?categoryid=1082&cs=1, which misquoted the box office return of The Day After Tomorrow as a $200 million film domestically when it only grossed $186 million. It also was slightly off on Star Wars III's gross: 380 million. The article is more accurate in taking into account production values but it doesn't say how much in advantage the number of sequels give one summer over another.