There are hundreds of exceptions, black knight armor, khamset armor, severii armor, ancient armor..... recipes are still being added, like the scale boots and gloves.
Having the crafted list seperate makes it easier to keep that up to date as you are only going through recipes that are actually avaliable to each craft, there is also the possiblity that recipes may be removed/modified, unlikely but still possible, you would then have to seperate the recipe from the old/original crafted result again in the database
Two seperate sections allows for more flexibility and its easier to amend if needs be
Related discussion - I fail at post titles

http://www.dfo-db.com/forum/about-dfodb/0_39