sorry, but i dont read the scripture as you do - but very very similar. for me it only says that the scripture is the perfect base. it doesnt say ppl MUST use it alone. other books are possible, when they doesnt twist scriptures (what most jws falsely believe is true when it comes to wt books)
but, youre absolutely right, it doesnt say by FAR, that one MUST use other books as well to have a benefit.
clearly the wt library 2007 is wasted ressources ;-)