BGS said they are using the loomis study?
Its just a proportion guide, done by Andrew Loomis. Most professional artists keep a library of books, guides, and sheets as references.
They didn't say that, the concept artist has it up on the wall behind his monitor. Its not a big deal though really, its just a reference sheet for him. Just like he has a book on vikings as well... but it doesn't mean that BGS has said "this is our official guide!"
If you are interested in that kind of thing, you can find it here: http://www.scribd.com/doc/255814/Andrew-Loomis-Figure-Drawing