I dont think the relation to Pierre Closterman is fully relevant. Notice that he mention more than 40 AA units firing. In the AH field defence is much less.
I was an AA man and know this in AH is unreal. Even when we had radar tracking of guns we could not achieve a hit rate like in AH. On manual control of guns its very hard to hit anything unless its coming straight towards you, or going straight away.
The AA tactic was alot about making a wall of fire for the planes to go through, and hoping for hits by scrapnell, and disturbing the pilots aiming.
When training AA on drones we may get a classified hit every couple of tousand rounds. And drones where slow and going in a straight path.
On fast planes, like jets, we couldnt even move guns fast enough to track them, unless they came at a very low angle towards, or away from us.