Please take a look at this recent discussion thread:
https://connect.mayoclinic.org/discussion/macntm-is-different-for-everyone-treatment-might-be-different-too/
Everyone of us has a different experience with Bronchiectasis and MAC, so no single protocol is right for all people. That is why we need to be very careful when following recommendations from others, especially if there is any insistence that "everyone needs to do this."

Here is a very sound philosophy for airway clearance - If it makes you feel worse, don't do it! Here is another - from my pulmonologist and respiratory therapist - after you neb, ten minutes of airway clearance and no more, unless you are still bringing up significant mucus - it will only serve to irritate your body. Remember, it is normal to have some mucus in your lungs.

My bronchiectasis varies greatly depending on my general health, the state of my allergies, how my asthma is behaving, and whether I am having an exacerbation. Most of the time, with airway clearance, I bring up a TINY amount of mucus - less than a teaspoon a day. But if I get an exacerbation - whoa! It seems like a quart - but is probably really a half cup. (PS I haven't had a real, serious infection in 2 years with this method)

Finally, dry bronchiectasis is a real thing - only recently recognized. I plan to do a little searching and see if I can find some expert info on how to manage it.

Have you brought up this issue with your doc? what is their recommendation?
Sue