Well I am sure you see what you see, I do not doubt it. But I can assure you I have "twitch twitch" flown a lot of planes in campaign and QC whilst testing the many things we have to, making the flight models etc.
I see all sorts of behaviour, for example try DVII v random skill Camel, if they all dive to the deck everytime, then I'd suggest something odd going on because here they nearly always stay high.
If you do not already, I suggest you choose the default QC Dogfight mode, and Enemy Situation:normal - you may see a different behaviour.
BTW some tactics used in the war for example Albatros would often fight using slashing attack not stay and turn fight.