Froggi, you know I loves ya, man....but I have to take a slightly different route. The "lung capacity" test that you take by blowing into a tube doesn't tell that much about your lung function. It's actually one of those tests that reveals more when somebody does horrible on them. I guess what I'm trying to say is that just because you did good on that particular test doesn't exactly clear you of all pulmonary problems.
Could this be just another money grab? Sure, it might be. But when a lung specialist ends up ordering more tests than the bariatric nurse expects, he may be seeing something that gives him pause. At the very least, he may just want to be absolutely certain that everything will go smoothly on surgery day.
If you really really suspect that the pulmonologist may be ordering unnecessary test, tell your bariatric doc that there's no way you can afford to pay for all these diagnostic tests, and is there any other way to get your surgery done. Maybe it'll work, maybe not....
Either way, you know I'm on your side here.