What was the specific reason Sai Baba demanded exactly fifteen rupees as Dakshina from Shama? The text seems to imply a deeper, symbolic meaning.

The account in Chapter 18 describes Madhavrao being sent by Sai Baba with a message to collect 'fifteen rupees as Dakshina from Shama.' While Madhavrao is surprised and Shama offers 'namaskar' instead, the text does not explain any symbolic meaning or specific reason for the amount of fifteen rupees. The narrative focuses on the surprising nature of Baba's request and the subsequent interaction, highlighting Baba's unique 'play,' but the significance of the specific number is not explicitly stated or clarified in the source material provided.