One would think that the average would stay constant because for each kill normally there is a death.
The only things I can think of that would make is rise, is less people exiting vehicles with out getting killed or getting a kill.
Any other thoughts?
There are more GV spawns to the strats
And there is Buzzsaw. Buzzsaw has GV spawns to enemy strats from the start. And when you play on that map, you will see all strats in reach flashing almost all of the time from GV. I would not be surprised if the amount of damage points generated on this map is ten or even twenty times higher than on other maps.
You also have relatively little defense against those strat killers. In my experience you can sit a long time there shooting buildings until a serious defender shows up. Which may have something to do with the fact that the strats are basically indefensible anyway. Most of the time it's more like "I shoot yours and you shoot mine".