The +1 Bonus to Discipline for every 4 levels of Mystical Skills is being removed. The only reason it was implemented was to keep casters on par with the Physcal Sheets and Other Breeds by giving them that bonus. Since nobody else gets this bonus, they won't be getting it either anymore.
When you run GM'd Events, or are Hosting, please be aware than no Magi, Psions, or other Breed using a mystical skill to cast will gain that Bonus for having Mystical Skills at 4 level intervals.