@Baron:
I tried to apply your formula to a special case.
For instance, the defensive picket made usually by Russia to prevent Germany’s blitzkrieg while retreating main force behind this front line.
Usually, you need to commit 1 ground unit, as much as possible the chespest: 1 infantry.
But your formula seems to show that it can be more cost effective to put 3 Infs, even if it costs 9 IPCs to inflict more casualty to the attacker.
At 1 or 2 units, it keeps the same ratio for the investment (1.25) but beginning with 3 units the stack get stronger per IPC invest (2.00).
Often, the picket Inf brings no result except blocking but if you block and get 1 casualty or more, it is far better.
So, does this formula is showing a better use of unit in this tactictal retreat?
Simple answer is no, it does not. For two reasons, 1, your goal with the scirmishers is not to inflict dammage, but to prevent blitzing. So the purpose is different. And the other reason is covered below.
Longer answer is: The formula does only give the strength of the stack, you need a different formula to figure out what damage that will result in. If the stack will die anyways (like your example) it might be that adding the 2 extra inf not will inflict the needed 6 ipc of damage to the germans attacking it.
On an extra note:
@Baron:
But your formula seems to show that it can be more cost effective to put 3 Infs, even if it costs 9 IPCs to inflict more casualty to the attacker.
At 1 or 2 units, it keeps the same ratio for the investment (1.25) but beginning with 3 units the stack get stronger per IPC invest (2.00).
Often, the picket Inf brings no result except blocking but if you block and get 1 casualty or more, it is far better.
It actually shows that a bigger stack is more costeffective than a smaller. So if you have 50 units, it it better to have them in 1 big stack, rather than 2 smaller. it is a more costeffective way of fighting :) But I guess everybody already knew that ;)