Can you explain the incident involving the two gentlemen from Goa and Sai Baba's unusual request for Dakshina?

The source material describes an event where two gentlemen from Goa came for Sai Baba's darshan. As detailed in Chapter 36, Baba's interaction with them was quite perplexing to onlookers. He specifically asked one of the men for a Dakshina of fifteen rupees, which the man gave joyfully. However, when the second gentleman voluntarily offered thirty-five rupees, Sai Baba immediately rejected the offering. This apparent partiality surprised everyone present, including Madhavrao (Shama), who questioned Baba about his actions. Baba's initial explanation was that he doesn't take anything for himself, but "Mother Masjid demands what is owed, and the giver becomes free from debt," hinting at a deeper, karmic reason behind the exchange that transcends simple monetary transactions.