Well, upgrading your account would only cost a couple extra dollars per month (or whatever currency you use) as opposed to the full price of an extra transfer. That way you could transfer your main to tonberry without transferring your alt first or having to delete it, and it would give you some extra time to decide what you want to do with the alt.

Unfortunately, the free transfers are only for players transferring off of Chaos data center due to changes in gameplay caused by the move, not onto it, so that idea wouldn't work.