You should be aware, however, that the number of men and horses is entirely for flavor, and no game mechanics make use of the number of men. The "number of men" reported comes from the number of hits (hearts) an element has times a fixed multiplier that varies per unit type and is available in the model game files somewhere.
The game keeps track of casualties, build cost, supply usage, replacements etc. at the hit (heart) level or higher. When looking at a battle result, for example, ignore the number of casualties, pay attention to the number of hearts inflicted/received by each side.
The unit panel does not directly report on the number of hearts in a stack, so the "number of men" can give you a ballpark estimate of relative sizes, but the PWR rating is more reliable for decision making since it also factors in cohesion, quality and leadership.