John Lowe in his book does make mention of how pro players have "unique" throws that they have developed and perfected. The advice that he was giving is directed more, in my opinion, at this is what you should try to do to start. Then, as your game and throw develop you tweak it to your own personal preferences.
Like grip said, no two people's joints behave identically. So, it is only natural to see a variety of stances and postures that can all produce the same results. The trick is to learn what yours is.
I do also believe that the more you allow to move, the more you have to correct for. So, by minimizing the number of movements there are in your throwing action the more likely you are to throw consistent darts.