The point Cost listed for the Detonator in the equipment area was, like all the pC's in the equipment section, left on by accident and wasn't meant to go to printing.
As such, only one unit can use Detcord but if you want to use it for anything other than obstacle clearing, you're insane. As far as Obstacle clearing goes, either C9 or Detcord work equally well for the cost. So really, it's more or less a non-issue as future units will recieve remote detonators and current units will (almost) never use C9 as an offensive weapon.
-PFC joe