Myself and other people have noticed that too. I personally stopped used that diet plan and use
http://www.mypyramid.gov
You can never get the diet plan right but you can try to get it close. If you want a finicky diet plan then do this,
Find how much protein you want, then out of those proteins decide of how of each kind your going to eat. Not all proteins are the same, different amino acids combinations make up different proteins. Different proteins absorb different and you need different amino acids.
And thats just proteins alone. Nobody really wants to do that so don't be so precise. Be close, but not precise. And not every diet plan is for you, your body may respond different to different things. Maybe you don't like a certain food. These things happen all the time, there are always more than one way to do things.