Whether you adjust via volts or adjust via watts, you are essentially doing the same thing. You are adjusting the power output up or down, just in different ways. With volts, you are simply adjusting the power you device puts out to the atomizer manually. With watts, you are still adjusting the power it outputs, however the device detects the resistance of your atomizer and adjusts the voltage in accordance with that resistance. Watts is just a calculation between resistance (ohms) and volts. When you adjust by volts, it's like driving a stick shift, where you need to adjust the gears according to how fast you are going yourself. When you adjust by watts, it's like driving a manual, where the car switches gears itself after detecting how fast you are going. Once you find a "sweet spot" in watts, you can just leave it at that setting, and when you switch the atomizer and it has a different resistance, your device sets itself to that same sweet spot without you needing to readjust.