It is this deviation that makes value investment successful! Because if there is no such deviation, the price will not be lower than the value, and value investors will have no buying opportunities. If there is no such deviation, the price will not be higher than the value, and the value investors will have no chance to sell! It is this deviation that gives value investors room for arbitrage!

In fact, if you can get the deviation between price and value through the analysis of this model, you will actually overturn the viewpoint of "market efficiency theory" in the textbook, and you should be able to appreciate its value.