Round1: regiment1 fights and lose 10%
Round2:50% chance to stay and fight, or run away screaming
If stays Round3:50% OF 50%(total chance) to stay or run away thats 25% chance, and so on, thats where the lower percentages come from. Lower percentage of STAYING, so it means the more rounds a regiment fights the more likely it is it will run away IF it loses 10%.
This is very weird on small regiments. But when big regiments fight with hundreds of troops in them, the chances of running is not that high cause from a regiment only 10 troops actually inflict damage each round. So the time a regiment of lets say 500 troops to loose 10% is much bigger then a regiment of 10 troops losing 1.
I realy dont see any better way to explain it.

Thank you. That clears it up.

and what you cant understand? once your regiment loses at least 10% people it has static 50% chance to run every turn.

or you mean this:

to stay 4 turns regiment must not run in all 4 turns. so 50% for round 1, 50% for round 2 and so on:
50% * 50% * 50% * 50% = 6.75%
thats the chance regiment would stay after 4 turns

no. they are at 50% each round.

I don't think I'll understand even if we discuss it for hours. Is it gunna change?

so when regiment loses at least 10% people it has:
- 50% chance to stay 1 turn
- 25% chance to stay 2 turns
- 12.5% chance to stay 3 turns
- 6.75% chance to stay 4 turns

and so on

you will find more here:
http://en.forum.dolumar.eu/topic/140/too-early/page/4/

now the dead units isn't the problem. But look at the victory percent. It doesn't look right to me. but maybe I'm wrong. Can anyone clarify?