I will start out by saying that yes, realistically there is a huge amount of time between this due to distance and reaction times. However, often times when I give the calls for mortars and artillery to smoke out or bomb out a location, usually at the start of a counterattack, the rounds do not impact until the area is secure and we are clear to move up.
There is also a big difference in the calls for Security air support that arrive almost immediately and lack of quick response support for Insurgents, despite the Insurgents basically fighting in their home towns.
Has anyone else felt the same about the fire support? That is, if your Observers and/or Commanders were ever together half the time.