Laying guns on target (in case you didn't know)

[Xandor]

That then could be used as a double bluff, possible scaring your enemy away from a targeted position without even having to fire a salvo.
That 'double bluff' aspect is a SP game tactic, not RL obviously,

Well, I, personally see "shell sound" in game as 1-2 ajustment shots before unleashing a full weight salvo, that was common practice in pre-ground radar and computerized fire control artyllery. 
And sometimes it leads to "double bluff" tactics and avoiding targeted terrain tactincs in RL. At some WW2 sources (e.g. Gen. Lelyushenko's memoirs) were mentions tank column avoiding crossroad after recon team spotted some fresh shell craters (indicating that this crossroad was zeroed by german arty).