If you read the transfer stuff closely, the 'Destination' servers this time around are a bit of a misnomer--they're listed in the 'Origin' servers as well. My guess is that all
servers in the Origin list were migrated onto new hardware (with the High Pop Server Tech installed on it) and it's just that one of the names was retained after the migration.
As another commenter mentioned, who got to retain the names was more complicated than the last round of transfers, where it was 'whoever was there first got to keep it'. From a comment made during the High Pop testing last week
"Based on this test of the transfer system it appears to be the character that has had the name longer. I saw this based off of some comparison with my own toons and some of my guilds toons. So if you created a character on origin server X with the name Hans and someone else has a Hans on sever Y and you both are getting transferred to server Z then the person who has had the name longest appears to get claim over the name."
There are probably some other factors at work here, but--there's at least one possibility going on. You probably can't know how your character's name seniority is going to rank against someone else's.