Draft Class Star Limit Reached

Franchise mode during week 1 prior to draft class generation adjusted all draft positions slider to very strong.  Maxed out all star, superstar and x factor players in league settings.  Week to vegan to edit draft class and after editing 38 players mix of normal through x factor I receive a message star limit reached.  I then went through and changed some of the stars to normal and stars to superstar. Saved the draft class imported the file again and received the same message.  2 questions first what is the max number of star superstar and x factor per draft class?  Second if I change a player from Star to normal and import the draft class why do I not have the ability to add more star players?