Well, it seems he has decided what he likes & what makes him feel most comfortable. Maybe just continue to let him dictate his step up comfort level & don't try & do anything different. In time you most likely will find that he decided to change things up once he feels totally secure & trusting that you will always do the same thing each time. It can be frustrating for you, but he is probably frustrated that he never knows how your gonna try & get him to step up. when he is ready, he will let you know by doing something different. I think patience is the key...:)