Not for the sake of argument, but, you say… “This is not all that unusual for after action reports, regardless of the army, the period of the war, or the rank of the writer.”

Granted, estimations of enemy numbers were poor throughout the war. However, I believe that folks like Leftwich may have been able to better assess numbers they faced as the war progressed. I think it’s simply a reflection of the green soldier becoming the veteran. It might be pretty neat to go back in the regimentals (especially those published for the HE Howard series) and assess the reports of commanders at various levels, and as the war progressed, to see how their ability to judge enemy numbers changed.

It would take some legwork, but I think this type of thing would be an interesting thesis for someone to develop.