Is Entourage's Alan Horn a misinterpretation of the actual man?

While curiously reading The Man Who Heard Voices, Or, How M. Night Shyamalan Risked His Career on a Fairy tale, I came across a rather interesting section of the novel, which is fantastic, anyway. After the very well known split between Disney and M. Night over Lady In The Water, he took the film to Alan Horn -- President of Warner Bros. Pictures.

In the novel, Alan is described as a "relaxed, subdued kind of man" that believes solely in "fate" and kind hearted. Definitely not something you would expect from the President of the one of the biggest studios out there? And this would bring me to Entourage's portrayal of him. If Harvey Weingard can be a raving lunatic -- which is similar to Harvey in real life, as said by many -- why can't Alan become a relaxed and focused man?

Obviously the story for the second and third season had the move, and since Doug Ellin had himself in a rut, he made Alan out to be the complete villain. It's understandable, sure, but Alan Horn isn't at all like what they've been portraying him as.

I say: show a more human side to him. I'm sure the real Alan, who has more than likely heard of his character on the show, would love it.