Based on this story, it isn’t clear that they are following the best model for church planting. It could be, however, that they already have a core group and are now ready to take the ministry public.
I was also going to say that that isn’t a strong area for Anglicans, but I see that Kingsport has three Episcopal parishes (only one large enough for a web site, apparently).
My experience with AMiA is that it does not particularly target current or former Episcopalians and seems to prefer the unchurched and evangelicals from various backgrounds. I was clearly given the impression that AMiA did not see its core ministry as providing a safe orthodox haven for alienated US Anglicans as CANA does.