We just discussed this in another thread.
It is the way it was set up, you can drawn the same chit more then once.
Of course it is wrong. I do not care about multiple PKs, but it lowers the chances to down a plane when you score a lot of Rs.

I think it is on the to do list of our beloved skymasters, which I hope reads something like this (just a reminder, we appreciato very very much your work ):

1) Correct damage chit drawing
2) Tailing in the same hex
3) Free tailing of friends
4) Fix the fire bug (the Fire/Smoke Extinguishing Step should come after the combat step)
5) Burst lenght (and possibly lewis guns)
6) New medium map size (10x12 instead of 12x10)
7) Planes do not showing special damages to machine guns
8) Automove

I hope that all of this will be fixed after the WS&IM project will be completed...
please please please