Wempe and Cellini, both in NYC, were the only US ADs until 2002. Cellini had two former stores (Madison Avenue and their amazing Waldorf location), and Wempe had one store (still at 55th and 5th). So basically all US Lange AD's, as well as all of Lange's authorized servicing in the US (i.e., Alkis), were literally all located within about a 1/2-mile radius of Madison Avenue & 50th Street! Then Lange opened 5 more ADs in the US and Canada. Alpha Omega was one of those second-wave ADs.
Also, the gray market for new Langes in the US was very, very robust for about the first decade after the relaunch. There were a handful of US "gray-D's" whom it seemed like everyone knew. The economics were quite different back then, and I think it was a bit more difficult for US customers outside of NYC to establish relationships with distant ADs.