i dont think the history is made up, or he would say he created Shou Shu because you can tell its not Kenpo and id say that its a lot more effective than Kenpo and that would make him a bigger genius than Parker.
Like I said, what personal experience do you base this on(the superiority of Shou Shu I mean)? There's actually a very practical purpose for making up history, and that's to make money. People watch a lot of kungfu movies and are easily impressed by fantastical histories and legends. Atributing silly titles such as Da Sifu to tradition gives him a legitimate reason to put himself on a pedastal to feed his own ego.