My pulmonologist put me on 3% three years ago when I was first diagnosed. It was thru this site that I learned about 7% - a huge difference!!!!! As soon as I am done with nebulizing I begin to cough up clobs of mucous. I use 7% in the morning and 3% in the evening as coughing after 7% interferes with my sleep. I asked my pulmonologist about 7% and he said he had no problem with ordering it. Saline has no medication in it so insurance and Medicare will not pay for it. It is relatively cheap and my daughter who has been an RN for 30+ years told me that no prescription is required. MAC is rare and I 100% agree that no pulmonologist is an expert and they would learn a lot if they listened to those of us who have lived with it for some time.