That's how every treatment for autism is. For some people, it's a miracle, for others, it doesn't do anything, and then sometimes the child happens to regress again. For the kids who I know, just having the right person in the room puts a light in their eyes, something clicks, and they will have a full blown conversation. For others, they are at their best after Occupational Therapy, and then for some others I've met, cod oil has seemed to magically unlocked the secret of speech for them.
I'm not sure how they can so easily just come up with any sort of treatment for autism, any day. The results vary from person to person far too widely to have proof of much more than it's existence.
We just need to know more about how exactly it works...