Ellie's vet told me that she learned very little about nutrition in vet school. She said if I have questions I can go online and/or talk to a nutritionist. Thankfully she doesn't stand there and try to answer questions when she know nothing about the subject.
Anyway, from the small amount of reading I've done on this, a food can be considered all life stages by AAFCO if it passes a feeding trial. Some people don't think this is good enough because they are only 6 months long. That is what I know so far...