Um, Marla, something is rotten in the state of Denmark. Anything is possible, but I think when your instincts tell you something, its generally a good idea to trust them.
M got his vest at 6, when he came home. Our clinic said they can start babies at 6 months. But, M's old clinic never even offered him a vest. I have a lot of speculation on why he was never offered a vest before, but it would only be speculation. The important thing is that he has his vest now, and he happily tolerates using it twice a day. He will scream and tantru about the nebs. But, he still thinks its cool to talk and sing while hooked up to the vest to hear and feel the vibrations--which only helps clear him even better!