I don't know if my answer is what you're looking for...I don't know if it increased my pft's. However, used twice daily, it has helped my airways stay more open between breathing treatments. I think that alone is worth it, regardless of pft numbers.
Oh, and...
Inflammation in and of itself can cause lung damage - so the less inflammation, the better, even in the long run.
So, for both of those reasons, I think it's worth it.<img src="i/expressions/face-icon-small-smile.gif" border="0">