Location, location, location

Looking for children's books at Borders my eye immediately spotted a Level 1, shortly followed by Level 2... but where was Level 3? Surely, if you go to the trouble to arrange books in levels, two is too soon to stop. Hardly seems worth the effort. I was about to give-up when I noticed the bottom shelf. Obviously, the wrong location for a top shelf name like Level 3. Not only that, but unlike the two preceding levels, it was forced to share space with "& 4". Poor form, to say the least.