I think what the poster says is: since it's a custom battle and he gave the exp to the Urbaners (say he gave them 3 exp), he expected (and i would) that all the 82 soldiers (normal is 82 for them i think) would have the 3exp, thus making the unit a 3 exp unit in total.

When the battle was over, the unit had killed 2xx men, while 12 were alive. So, even if the 12 survivors, hadn't made a single kill (quite unlikely, but it doesn't matter), the unit should be at the starting 3 exp he gave them in the "buy ur army screen".

Before reading this post, i knew of course that in Campaign battles, units have veteran soldiers and green one's and if u sent a unit of 2 exp with 50 ppl and 20 survive, it could be that even if the survivors made some kills, those killed had more, and thus, instead of the unit gaining exp, it lost, ending in exp1.

But after reading this one, i have to wonder, cos the only logical explanation is that 3 exp is divided as 1/3 of the men having 1exp, the other 1/3 having 2 exp the rest having 3 exp. Or it could be that half the men are green and the other half are 6exp, averaging down to that 3 exp unit in total.

Some explanation on this should be given by the game developers i think, on how the game allocates the exp you buy in the custom battle screen among soldiers.