Well, it was on Yahoo the other day, Nigel Lithgoe, (producer of AI), said that Haley had 25 million votes out of the 95 million cast. That is reportedly the only time vote totals were ever given, even in rough numbers. That's one heck of a lot of votes.... except that if the other 70 million were split evenly, she lost to each of the others by 10 million. During the David Cook/David Archuleta finale season, the vote totals weren't ever announced, but it was announced that it wasn't even close between the two, that Cook won handily. In both instances, Reinhart and Archuleta were the VFTW choices.
My guess to your question about 5 contestants is still that I think they are insignificant. They can't really vote anyone OFF. They're more like a rooting section marching to their own beat, getting people riled up on purpose. They MIGHT have kept Sanjaya around one extra week, with the help of Howard Stern's listeners, but it's not like someone who was going to win got booted instead. It was more like the order in which people were going to lose was shifted around. Maybe.