How did Sai Baba attend Dev's Udyapan ceremony, and why was Dev initially so disappointed?

Sai Baba attended Dev's Udyapan ceremony not in his physical form from Shirdi, but in the guise of a Sanyasi. As detailed in Chapter 40, Baba had promised Dev he would come with two others. A Sanyasi and two companions did arrive and were fed, but Dev failed to recognize him. Dev was initially disappointed because he expected Baba to appear as himself and felt that Baba's promise had "turned out otherwise." He wrote to his friend Jog complaining that he felt deceived and that no experience came to him despite waiting with great effort.