Can't find an answer to this on the interwebs, not even sure if this is an "appropriate" forum sub-category for this but essentially my buddies and I are stumped as to why swapping an armor mod affinity from either void or solar TO arc requires no upgrade module - and I mean specifically for armor pieces without any mods installed (obviously) and swapping to a base 1 energy arc affinity - it costs nothing! But doing the same costs an upgrade module for the swap from void to the other two, or from solar to the other two and we're just trying to figure out if this a bug? Some undescribed intrinsic benefit of arc mod affinity? As far as we can see and research there's no explanation as to why swapping to arc as previously described costs nothing (not that I'm complaining about it either... cus yay, but we're just confused as heck).