My reading has improved

One child I am working with has improved his reading level by a year.  He still needs to improve to be on grade level but he is seeing success.  Therefore he does not think he should keep doing the balance board and the exercises that go with it.  He just wants to get on with his success and learn to read better.
I asked him if I made cupcakes and iced them if he would eat them.  He laughed and replied, "Of course I would."  I asked him if I iced a piece of cardboard cupcake, if he would eat that.  He replied, "I would lick the icing off."
I told him that the reading is the icing on the cake and that if he did not keep working on the balance board it would be like icing the cardboard instead of the cake.  He might keep getting better with the reading but it would take longer.  He did better working with me but he is only half way convinced.  I also realized the board was getting too easy, so I moved it up a level.  I learn more than the students.