Turning off skirmish is Fire-by-rank, Skirmish mode is individual fire (only first 2 ranks will fire)

Although gunpowder shuffling was improved, the line has to face the enemy so they'll reform the WHOLE LINE in 30 degrees or more to face the target and fire. Of course by then theyre behind your other infantry and whatnot and simply not firing. Fire by rank, as of now, is stupid except for the last miunte volley under a roof of pikes.