Yeah, doesn't work then. I have had 3 or more supply wagon units, at full strength in many different regions and never been able to build a depot.
You are correct on page 23 it does say that, I went right over it. It would have been nice if anywhere in the SUPPLY CHAPTER, where I looked, it had mentioned depot cost or a link to page 23.
I guess the question is how many elements are needed to start a depot. Not how many units.
Are all of the Allied supply wagons understrength? Is this a deliberate design decision? If it is I do not like it because it clashes with a decision they made on elements. I can have an army with 180,000 men in it and it will have 10 or infantry elements... which causes entire elements to be wiped after single battles.
In my current game the French 3rd and 4th army after one fight had zero infantry elements.. thus I had to find a depot to move them to to get new elements.
If I were to design this game each infantry division would have 4 elements early, and 3 later war. 2 per division does not work, they should have known this from making the first Napoleon game where there were few elements thus total element death in every battle.