but you can be entitled to perks, no? shoot down 10 planes, you are entitled to x amount of perks?
It depends on the perk bonus, for example.
When the perk multiplier is at 1: (all the countries are even numbers, or about.)
If you shoot down a Spitfire Mk. 16 in a Spitfire Mk. 16, both 5 ENY planes, you will get one perk.
The ENY of each plane is divided by each other.
ENYa / ENYb
Then that number, in this case 1, is multiplied by the perk bonus of 1, you get one perk for the kill.
It goes the same for all planes, even bombers. If you nice there is a number for OBJ, this number represents the destructiveness of that aircraft, all fighters have an OBJ of 10.0.
Bomber's OBJ are different depending on their destructive loads, the B29 is the lower end of the spectrum for OBJ meaning you will get less perks for destroying something than if you were in a B5N, the upper end of the spectrum at 40 OBJ.
I am not sure what the ENY of a town building, or other objects are, meaning what number they are given to plug into the equation for perk outcome. (OBJa / OBJb) * perk multiplier.