| Scythia |
I've seen your thoughts on that Rynjin. :P
I can't find a reason they don't stack either, but the only similar things I can find for a precedent are the rage powers Lesser Elemental Rage, which adds +1d6 elemental damage for a round, and Elemental Rage which adds +1d6 elemtal damage to every attack. Those can be used together, but must be used to do different types of elemental damage. Although I suspect that has more to do with simply being different versions of the same power.