If every pin was exactly the same, down to microscopic levels, and all the holes were drilled to exactly the same width and placement all the pins would bind at the same time regardless of what order you put them in. But here in the real world....
Because no two pins are exactly the same binding order tends to change when you change the pins around.
"We all sit around in a circle and suppose, while the secret sits in the center and knows." --Robert Frost