In general when you have UVs on your set they add up and are caped to maximum. (IAS for example)
What happens when you have an armor and a helmet with both UV's at maximum defense for elemental for example, do you get more overall elemental defense as if you only had one of them with that maximum UV ?
you'll get both those UVs
generally, the weapon UVs only go up to level 6 Maximum, while the armour UVs don't really have a cap