The coder’s blog post tells you how it works. Reading that post explains how it took 14 steps from both Kraftwerk to Professor Longhair AND Roska to Professor Longhair. Each reload gave a slightly different path, mostly using different songs from the same artists.
Asking to go from one long tail artist to another quite different long tail artist yields a larger number of steps. Not surprisingly, it took me 23 steps to get from Disclosure to Iris Dement.
Then you can make them go backwards too!