What happened with the Dakshina when two men from Goa came for darshan, and what was Madhavrao's reaction?

The story from Chapter 36 details an interesting interaction involving Dakshina. When two gentlemen from Goa came to see Sai Baba, Baba asked for fifteen rupees from only one of them. That person joyfully gave the amount. The second man, unprompted, offered thirty-five rupees, but Sai Baba immediately rejected it. This action was perceived as partiality and caused great surprise among the onlookers. Madhavrao, also known as Shama, was present at that time and, seeing this, decided to ask Sai Baba to explain his reasoning.