How did Sai Baba sleep, and what was so unusual about his sleeping arrangements as described in Chapter 10?

According to Chapter 10 of the Shri Sai Satcharitra, Sai Baba's sleeping arrangement was highly unusual. He would sleep on a narrow wooden plank, just four cubits long and one span wide, which was suspended from the rafters with old rags, like a swing. The chapter notes that lamps would burn at his head and feet while he rested. What made this so special was that his movements were imperceptible; no one ever knew when he climbed up onto the plank or when he descended from it, adding to his mysterious nature.