Follow up!
So I called them, the nocks/batteries can be changed BUT you have to stay with that style/brand of nock as the inserts which are aluminum are glued in.
Reason for having to stay with that brand is supposedly they are the only nock company that can produce a half moon nock that will handle the stress of the Mission crossbows in the Sub 1 line or I think he said MXB line?
Other nocks without the aluminum inserts will start mushrooming/splitting the end of the shafts after a couple shots.