Why did Sai Baba accept a 15 rupee offering from one man from Goa but reject a 35 rupee offering from the other?

The provided text from Chapter 36 sets up this very question as a point of intrigue but does not supply the answer. It narrates that two gentlemen from Goa came for darshan, and Sai Baba asked one for fifteen rupees, which he accepted. When the second man offered thirty-five rupees, Baba immediately rejected it. The text explicitly states that this act of apparent partiality surprised everyone and prompted Madhavrao (Shama) to question Sai about it. The reason for Baba's actions is the mystery that the chapter begins to explore, but the explanation is not contained within these introductory passages.