One Lingering Question

As I reach the end of the book, one question seems to have been haunting me since the start.  Why did Patricia Wood make Perry's IQ 76?  Why did she make it exactly 1 point over 75 (which Perry says that 75 is the IQ level for someone to be "mentally retarded").  I've already taken a look at great length to find out why Perry was slow (you can click here to go to that post).  However, it would have been simpler to make Perry's IQ an even 75 or less than 75.  Was making it 76 just an unnescary complexity?

In my opinion, this was one of the most important elements in the story.  By making Perry believe that he is more intellegent than an average mentally retarded person, he is able to have confindence.  That confindence fueled him to memorize words from the dictionary, and that confindence even fueled him to buy lottery tickets (despite his grandmother not wanting him too).  Yes, this confindence is somthing that seems to have dramatically affected the plot of the book.  Who knew that one IQ point could make such a difference/

(Interesting Fact:  If you subtract ten from 76 and put the number into base 16, you get 42.  Which is the answer to life, the universe, and everything.)