Five Point Someone to 3 idiots - Deserves more Credit?

By now, there will hardly be any Indian who has not watched the movie "3 idiots". I am one among the larger Indians. After the controversy broke on the "Story Credit", I was curious to know the fact myself and bought the book, "five point someone", by Chetan Bhagat. If i remember correctly, at the end of the movie, along with the list of people in the movie, which anyone hardly watches, a line appears "Based on the book five point someone by Chetan Bhagat". I personally believe that the "heart and soul" of story (of the movie) was taken from the book and hence deserves more credit than given. If the same line appeared at the beginning, things would have been different. Its my take.