Diver Dennis:As you can see, the quote in the OP does not indicate which way to push the lever to go up or down, just that using the lever you can control which way you are going, up or down.
Sure, but plenty other places including the AL website and magazine ads not only imply but state to "pull the lever up to go up" and to create "positive buoyancy to ascend".
It doesn't whether you use your lungs or BCD to control buoyancy. (In fact, I misrepresented what I teach by typing in haste - lungs are fine tuning, BCD is gross adjustment. ) The point is that you do not inflate to go up. No matter which bag you're putting air into.