Opinions about "Game rules as used by players"

[BigDuke66]

A question to the artillery rules, how far down does this count?
I guess it does not count for mortar within a platoon, but what about the extra mortars attached on a higher level.
An example is the 4th company within a German infantry battalion of WW2, these had MG but also Mortars in it, do I need an FO for these assets or do I use the company/platoon leader to assign them?
And what about the need to fire them as battery?