err yeah it is off. way off. I'd expect a chance of damage if I'm level 200mph, 5k, 4000yds from a large battery of AA guns, I dont expect to get nailed instantly while manouvering at 350mph, 20k, 6 miles out from the same battery ...
to say nothing about EW, MW and AvA/scenarios/snapshot from those years - the chances of getting hit by ack by those systems was negligible, unless you were straight and level for 10 miles+, part of a large formation of buffs and they knew you were coming.
anyone know how many fighters were downed by puffy ack in WWII while flying at med/high alts? I'm guessing hardly any.