Slitherine

Dad wants to know why if troops within 2MU of a crest can see over at any distance yet the enemy can see 6MU to see them ---- Aren't they 'hull down'???

Good point, one would expect many musket balls to fly over the heads of the troops atop the crest due to the angle of fire.
Maybe a 'minus ' POA' as target counts in cover ?

Musket volleys frequently went over the heads of the enemy even in a fair field at close range due to primitive levelling practices not well adjusted to the recoil from musket balls and their trajectory. The British are properly credited with being more advanced in this area. Shooting down or up a slope makes things worse.

I expect that the reason has something to do with the way that integral skirmishers are modeled in the game. Skirmishers are assumed to be up to a few hundred yards in front of the the main body. A unit behid the crest may therefore have a few men in front of the crest that can see the enemy and fire upon it if in range. The enemy may be able to see the skirmishers, but not the main body until it gets close enough for its own skirmishers to contest the crest (i.e. within 6MU).

Skirmishers, at least in theory, should be the best shots in the unit and hopefully be capable of adjusting their fire for elevation and recoil. They should at least have some practice at firing at inividual targets, rather than just following drill and opening fire en masse when ordered to.

Dad wants to know why if troops within 2MU of a crest can see over at any distance yet the enemy can see 6MU to see them ---- Aren't they 'hull down'???

Seeing and firing are treated differently. The 6MU medium range represents skirmishing light companies slirmishing out in front of the unit. Thereofre if you are within 6MU of the top of a hill you would expect some troops to advance in front of the main body to see what's behind the crest. If you're already within 2MU of the crest then you would junior officers at the very least to advance to the top of the hill, and also men from the integral skirmish companies (if it has any).