Because FC is not First Aid. For whatever reason, people have developed this idea that if it's not in First Aid, it CAN'T be tested over, and therefore any extra information in other review sources is just minutiae. Anything you learn in the preclinical years can be tested over, and people who have already taken step will tell you that their test included plenty of info that wasn't in a First Aid. First Aid is really there to give you the highest yield info, based on past tests, and it is not an all-inclusive review source. Bottom line, definitely learn all of the high yield info in First Aid, but then learn as many details as possible on top of that (depending on the score you are hoping for).