I have a druid in my game who has a minor rod of extend spell. If he uses the rod to extend his heat metal spell (or frankly any spell that does a different amount of damage per round for a certain number of rounds), how does the damage work. Does the damage still ramp up evenly, i.e. first round no damage, second round d4, third round d4, fourth round d6, fifth round d6, sixth round d4, etc. (I might have the damage from the spell miscalculated, but hopefully you all understand what I'm getting at), or does the spell work as normally and then starts again, i.e. first round no damage, second round d4, third round d6, fifth round d4, sixth round no damage, seventh round d4, etc. Hope my question is clear. Thanks in advance for any help.