1 extension of 180 - cost unclear as of yet. Have heard 1900b or as Much as 10k.
Exact financial and other qualifications are not set yet.
It is expected you will have to prove the money again worldwide BUT unclear of what will qualify as proof. AND possibly have to prove reason again, work etc.
This will be clearer as we approach the first extension.
Still too new.
They are pushing for exits and reentry rather than incountry extensions to keep in line as a tourist visa.