Counting planes in an airgroup

[salmo]

I've been experimenting with persisting squadrons during a battle. ie:
1. count squadron plane numbers at battle start.
2. Count squadron numbers when they land.
3. Destroying & respawning squadron for next mission with just their remaining numbers of aircraft.

I'm using the code below to test squadron/staffel numbers on aircraft takeoff & landing, but it's giving odd results.
(1) The console reports the correct plane total & alive numbers as each aircraft in a squadron/staffel takes off.
(2) The console always reports 1, 1, 0 when each aircraft in a squadron/staffel lands. ie. 1 total aircraft in group; 1 alive; 0 dead. irrespective of how many group aircraft are actually alive or dead at the time.
(3) The console always reports no killed or destroyed aircraft in any group, even when squadron/staffel aircraft are destroyed during a mission.

My question is, is this a game bug? or have I got the code screwy?

code removed by author