We've all experienced the frustration of returning home after a march across middle-earth with our hired units only to find out that many are now missing. You saw no death message, so what could've happened? You retrack your steps and then out of nowhere they teleport to you. You realise the issue is that they got unloaded along with the chunks they were left in while you zoomed on ahead. To make sure this doesn't happen again, every now and then, you count your units to make sure all are accounted for. A very tedious and annoying task.
I propose a very simple fix to this problem.
When a user uses a horn of command, the mod goes over all the loaded entities, performing a variety of checks:
Is this entity a LOTREntityNPC?
Is this NPC a hireling?
Does this hired unit belong to the player that is summoning?
And so on.
If it passes all the checks the entity is summoned/halted/readied.
So the mod is already iterating over a list. Why not just add a variable that increments each time a valid hired unit is found? And then at the end of the function display a message of how many units were effected to chat or some other form of display.
I believe this an easy feature to implement and would save everyone time, coin and potential headaches from having to count the number of troops they have.