Jody,
Ryan Jay is right: getting the right treatment is what matters.
Doctors group patients into diagnostic categories so they can analyze statistics over a large number of patients. They do, however, use these categories to study how an individual patient can benefit from what is known about research on groups of other patients, such as what approaches work best for patients with milder or more severe AA.
If you want the formal definitions of MAA, SAA, and VSAA, see our
Types of Aplastic Anemia page.