No, there is no 60-day window for
DAS. You can do the video chat to register for DAS no earlier than 30 days out from your first park day (which may be different from your resort check-in date). AND it's possible you may not be able to make Advanced Reservations until your whole trip (or first 7 days) are within that 30-day window.
The first post of
THIS THREAD explains how DAS works.