There has been *plenty* written about this, I wish the search function worked better on here. You could also look in the Help section of the game.. or the wiki.

This is part of the game, if their are not enough managers of one level to make a complete league, they can be combined with adjacent levels to make a whole league. And as stated above, often the compensation is better Scouts. Keep in mind too, this means you are near the top of your server, and the guys above you will have a worse Transfer List than yourself because there is no one above them selling down.