Units that are way too cheap/expensive

[PlasmaKrab]

By the way ZSU-23-4 Shilka fires in reality two HE and one AP round in one burst.

If so, then the AP ability of the basic HE shot (described 3round burst) should equal that of AP shots. And I guess they fire nothing else, so AP shots=0, right? Maybe there are many more autocannon units of this type, where AP and HE shots are fired mixed, but since both types were available, everyone considered they were selectable.

BTW, since we're talking ZSU here, I read a while ago a USMC report stating that due to command chain, a ZSU23/4 took about 30 seconds between target acquisition and first fire. I know all weapon systems have that kind of delays, but the ZSU-23/4 is pretty annoying in-game, having a considerable ROF.
Same with the towed ZU-23/2, about which I heard several RUssian soldiers saying that it was a terrific ground support weapon, but that sighting and aiming was much too slow against aircrafts.

I don't know what this data is worth, but shouldn't there be less shots per turn for these? They can follow a helo around as if on a magnet, and even strike aircrafts get their far share of shells.