I understand it can snap fire if it has advance or FF orders, it was more a question of if it can do it when on those orders and having already moved. Thus the comparison to a command unit.
The rules state that a command unit always moves normally and fires in the first fire phase, but if the command unit has moved, it can't later snap fire. Or if it snap fires before it has moved, it can't later move.
The Overlord is not a command unit, it just states it always fires in the FF phase unless on charge orders.
It seems a bit, what do you call it, gamey, since it resembles a command unit in the sense of moving and fireing in FF phase. I mean to be able to put down a FF order, move it 15 cm, and then use it to snap fire. OR what do you say?
One more thing by the way, there can't really be any difference putting down an advance or FF order for the Overlord, right?