I feel like a noob asking this, I've been mainly sub-ohm vaping on mechanicals and drippers for some time now, but I just received a few variable voltage/wattage mods such as the VTR, itaste134, etc. I kind of assumed that variable voltage/wattage corresponded together, I.E. setting my device to 15 watts, 6 volts would go hand-in-hand. Someone brought up today that they were told that when setting it on a device, you chose variable wattage OR voltage. Is this true? Or was this person wrong.