Home world transfer / prefered world

Hi , I would like to understand what exactly are considered a preferred world because I'm trying to move from a congested world to a non-congested world and it keeps willing charging me. I tried to move to another world (non-congested) I never played before and also tried to move to a world (non-congested) I already played and still have reroll in there and every time it still willing charging me so I really dont understand what is a preferred world.

"Service Charges
The Home World Transfer Service is an optional paid service. However, transfers to New Worlds, as well as transfers from Congested Worlds to Preferred Worlds, are free of charge.

Home World Transfer Service Fee
- $18 per transfer
- Transfers to New Worlds: Free
- Transfers from Congested Worlds to Preferred Worlds: Free"

Lodestone, News, Server status.

There are no worlds listed as Preferred at this time. Preferred is reserved for low population worlds, and everywhere is pretty populated right now. The only free transfers available right now are to the new OCE data center worlds.

oh I see, ty for your answer :)