Just fired a level 3 Hexbolt, targeting a Purple tile. No strike or protect tiles on the board, only opponent is Gorgon. Only 85 damage is dealt to Gorgon.
Scarlet Witch’s Purple damage alone is (exactly) 85 damage, so the power should have done additional damage for the other 3 tiles destroyed (or at least, it has worked this way for the majority of the time it has been a power).