Defensive Fire ?

[Nemo84]

From user manual, page 12

"Concealed units do not exert a Zone-of-Control."

If you dont fire enemy he cant know where are your units and move without zoc restrictions, VS an AI test i see how a Sherman unit simple run to my rear area without trigger defensive fire ... pass 2 lines of defenses  with no problem hehehe.

Yeah, but that's just a one-time occurrence. Once a unit has been spotted, it typically stays spotted and thus continually exerts a ZOC whether or not it actually fires more than once (and thus repeatedly exposes itself to op-fire). Also units can be spotted without actively breaking concealment.

Strela made it sound as if each firing action influenced ZOC, hence why I (and probably nim8or as well) became confused. Basically firing is not a macro-action with the intent to stop the enemy from moving forward and with defensive fire as a consequence, concealment is. A unit is typically concealed only once per game, but fires many times each turn.