Yes, but medium armour makes not real difference. For this money i can equip two lighter armoured soldiers or a few more peasants.
I dunno about that... It's pretty helpful when your average opponent is trying to kill you with a wooden sword or a cudgel.
According to the calc... 21 str, 7 PS, 150 wpf...
Falcion, 30 damage cut vs blue tunic = 44-49 damage, 46.5 average
Versus mail shirt = 12-29 damage, 20.5 average
So if you had, say, 65 hp, you'd die in 2 falcion hits with your Blue Tunic consistently but it would take 3-6 hits to kill you with your Mail Shirt. Add Mail Mittens and that takes the damage range down to 9-27, so it could take up to 8 hits. Make it +3 mail shirt and +3 mail mittens and now you're really talking, and it's not THAT expensive.
I don't know that you'd want to equip a 1000 man army like that but it's very doable for the 50-100 troop roaming warbands.
Of course, that's no great help against arrows.
Did I mention I also make shields... NH has Heavy Round, +3 Heavy Round and Plain Shield production capabilities! (Also Huscarl, but that's crazy talk.)