My level 4 Aedyran knight just enchanted a fine sword with flame lash to help put down shadows. However, from what I've read of the weapon elemental damage mechanics, it doesn't really matter what kind of element you add to the weapon. With elemental it appears that normal damage is calculated with normal DR first (pierce/slash/bludgeon), than a flat 25% of elemental damage is added to that damage. For example, against a shadow with a slash DR of 8, if I score a 'normal' hit of 20 damage, that leaves 12 points of slash damage. A flat 25% of fire damage for Flame Lash would be added to that amount (3 points in my example), for a total of 15 points. Fire DR doesn't seem to matter for this calculation, so it might as well be cold or shock damage.
TL; DR Does the *type* of elemental weapon damage even matter?