Arghhh.. I forgot to save my answer..
Lucky, this one was short, like this...
fifty-fifty... neither very precise nor abstract!
Each 'object' (town, village, castel, redoubt...) has several entries. The fighting is only on these sectors...
When the defence is broken, the unit A1 immediatly gets out.. and the victor B takes the place.
At this time, if there is some reserve, the IA (side A) sends a new unit (A2) which tries to take the object again... And this process may continue several times (like in the real battle)
Is it clear?
JMM