so I have 4 wired smoke detectors to install. the rough ins are complete but I think he made a mistake. there is 2 wire (black/white/ground) going to the first box, 3 wire going from the first box to the second box, but from the second to third and from the third to the fourth is 2 wire not 3 wire....... I think there is supposed to be 3 wire to all but the first? now I am worried because all ceilings are done and there is no way to get back to them to correct if needed........