You asked, "Is MAI essentially the same as MAC?" The short answer is yes.
MAI stands for "mycobacteria avium intracellulare" and MAC stands for "mycobacteria avium complex." Intracellulare is one variant of (I believe the most common) of the complex.
MAI is what this infection used to be called until improved technology led to differentiating between subspecies and the new name. That said, the way of treating each is similar - once the culture grows the bacteria, a "sensitivity test" is run to determine which antibiotics will be effective.

MAC is a rare infection, so it is usually outside the experience of general or family practitioners. In particular, they are unfamiliar with exactly when to watch and when to treat, and how to manage the rigorous 3 antibiotic treatment. Even pulmonologists rarely see it, so it is important to find one with experience, or to add an infectious disease doctor to your team.

We have a great group here who can help you learn all about MAC.
Sue