Why did Sai Baba accept fifteen rupees from one man from Goa but reject thirty-five from his companion?

Chapter 36 of the Shri Sai Satcharitra presents this exact puzzle but does not provide the answer within the given text. The chapter narrates that two gentlemen from Goa came for darshan. Sai Baba asked for and accepted fifteen rupees from one, but when the other offered thirty-five rupees, Baba immediately rejected it. The text explicitly highlights the surprising nature of this event, stating, "Everyone was greatly surprised by this." It further mentions that Madhavrao (Shama) saw this apparent partiality and asked Sai Baba to explain it. This sets up a question for which the answer is not contained in these specific excerpts, leaving the reader in suspense alongside the characters in the story.