Language changes as people evolve their thinking over time. If you read the book but don’t follow along on the site, you are going to miss out how descriptions of how things are working have evolved. This is an unfortunate side effect of writing a book, you can’t make constant updates to them, this is why the website and its content are valuable. Your last sentence is more in line with what is really happening when you use a band. You are using the extra pull from the band to help exaggerate a position of emphasis while patterning in a motor control change around the joint capsule and muscles by doing focused contract relax work and moving purposefully through the bookends of the range of motion.