This "premium" feature seems pretty basic to me. Seems like QBO made it part of their top tier "Advanced" for no other reason but to drive people up. How can adding a simple account number field to a customer be that difficult on the back end? 

Intuit assigns me, a customer, a number. So I think they know it's important for businesses to keep track of us, using numbers. Seems pretty pathetic not to have this feature.