One of my players asked why certain armors on his list (kung fu armors like 'Iron Shirt' and 'Mantix Reflexes' do not appear to augment his Dexterity.

Here's an example of Mantis Reflexes:


Here is the explanation:

These two skills do not add to the character's Dexterity. They add to either the Armor Class via the Armor Class Modifier (ACM) or the Damage Absorption (DAB). Usually armors, unless incredibly magical, will not add to Dexterity itself, and in almost all cases subtract from Dexterity due to bulk. In the case of natural or kung fu armors the effect is to increase the Armor Class (meaning it is harder to be hit). If the Dexterity increased then the character would have advantages such as increased Attack Level, which would not make sense for an armor to do. Since Grasshopper's Dexterity is naturally a 5, he gets a +1 Dexterity Bonus. If he put on armor such as a shield the Dex Modifier would be -1, which would mean he would have a 4 Dexterity, and the Dexterity Bonus would be 0. So the Kung Fu armor is special in that it increases either Damage Absorption, or Armor Class, but without the burden of bulk so it does not reduce the Dexterity. The more armor a character wears, usually, the lower their Dexterity due to bulk, (and therefore the lower their Attack Level). So Kung Fu armors give protection without costing Dexterity. But no, they don't improve dexterity either. That would be too much.