I heard a story about Baba asking for a large Dakshina of 15 rupees from someone in Delhi. Can you provide details on that?

The incident you're referring to likely has some mixed-up details, as the provided source material from Chapter 18 does not mention Delhi. It does, however, describe an event where Baba sent a messenger to Madhavrao, also known as Shama, requesting fifteen rupees as Dakshina. This entire interaction occurred within Shirdi. Upon hearing the request, Shama was very surprised and responded by offering fifteen 'namaskars' instead of the currency. This story illustrates a specific interaction between Baba and a close devotee in Shirdi, not an event involving a distant city.