No, a detection zone is the area in which it's determined if you're allowed to use DRS or not in the DRS zone. In iGP it's currently a line right at the start of the DRS zone, what's suggested here is to place it separately a little bit of distance earlier on the track.
A Pro is you see before everyone gets DRS if you get it or failed at it and can react somewhat. Also it could be placed at a sector time so you see why you got DRS or not, but the game could also just post the gap at detection point for that.
One Con is the effective track length to shake someone is reduced and makes it harder, because if the other car is within 1 second, like 0.9s, in the detection zone 75% around the track he can activate DRS in the DRS zone later even if it's a 1.1s gap now, which currently wouldn't allow DRS.
