Excuse me, some misunderstanding takes place.
2 battalions (20 figures each)
cause smaller (considerably smaller!)
or greater losses, than one battalion of 40 figures.
For example, as a result "7-8" (in the "Musketry casualty table") a battalion from 20 figures kills 1 figure of the opponent; accordingly, two battalions of 20 shooting figures each in a sum will give 2 killed figures. One battalion from 40 figures in the same conditions kills 4 figures, i.e. in 2 times more!
Another example. At a result 17-18 points two battalions for a 20 shooting figures will put to death 6+6=12 figures; at the same conditions for 40 figures have 9 killed, i.e. difference in 1,5 times.
I don't understand such mathematics.
If it interests somebody, original discussion of this question in Russian language here:
http://www.fieldofbattle.ru/modules.php?name=Forums&file=viewtopic&p=150017#150017