Can you tell me about Sai Baba's strange sleeping arrangement on a wooden plank that's mentioned in Chapter 10?

Chapter 10 provides a fascinating description of Sai Baba's sleeping habits. He would sleep on a very narrow wooden plank, described as being only four cubits long and one span (about 9 inches) wide. This plank was not on the floor but was 'hung from the rafters like a swing, tied at both ends with rags.' Baba would sleep on this precarious perch with lamps burning at His head and feet. The text emphasizes the mysterious nature of this act, noting that His movements were imperceptible, and no one ever knew when He climbed up to the plank or when He descended from it.