After the Undead Tribe arrived in Toril, the battles were either city sieges resolved within days or multiple forces attacking simultaneously... When they divided their troops, it was indeed difficult to discern the total numbers, since the Undead Tribe always managed to get lost in some peculiar places; deploying a million troops and only having two hundred thousand reach the destination was common, even though they had automatic following.
The only battle where the Undead Tribe participated fully was the defense of Agleya... But at that time, all attention was undoubtedly occupied by Suren, who emerged out of nowhere.
So, if it weren't for those with accurate intelligence under the deities, other forces on Toril would easily misjudge the total numbers of the Undead Tribe, especially determining the peak count.
Yet, the situation at Luskan was clearly a highly experienced regional task... The Undead Tribe would attempt to participate whenever possible.
