In title, so for each piece of armour, you can masterwork each element separately but unlocks that element forever. you can cycle through elements on each piece of armour right away, but if you want to max out the mods on a certain element it needs to be upgraded, this will persuade people to experiment with different build more often because it will cost the same as masterworking but 4x if you want to masterwork all 4 elements on a piece of armour