Can you tell me the story about Sai Baba climbing a ladder and what lesson he taught from it?

Chapter 19 narrates a peculiar event where Sai Baba taught a crucial life lesson. One day, he suddenly had a ladder placed against a house and, despite his physical weakness, climbed onto the roof. He then crossed to the adjacent roof of Radhakrishnabai, who was suffering from a high malarial fever. After this mysterious act, he climbed back down using the ladder. Immediately upon touching the ground, Baba gave two rupees to the man who had brought the ladder. When a devotee gathered the courage to ask why he paid so much, Baba explained the lesson: "One should not take the burden of anyone's labor for free, not even a bit." This story illustrates that one must always fairly compensate for any work received.