I believe that because the IPV-D2 uses a YiHi chip it has the YiHi "dry coil" detection feature.
It is my understanding that a properly wicked and wet coil can be pushed to the maximum temperature the mod supports (usually ~580-600F) without burning the wick. (as long as the wick+coil remain wet)
With the YiHi chip (others may have similar features) if the measured temperature slope as the coil is heated starts to rise unexpectedly the YiHi will cut power to the coil with the "dry coil" message. Hence you can't really 'dry burn' a coil with a YiHi chip in TC mode. (generally not recommended anyway for Ni and Ti wire types)
There are two-three distinct camps when it comes to settings. One camp likes to set to maximum power/joules and just let the mod try to regulate the temperature. On SX350J's if the joules is set to high the (real time) temperature can be seen wildly jumping over/under the set point. Another camp uses the minimum power/joules needed to hit the set point less than a second. There may be some battery charge savings with this approach. Lastly the other camp adjusts power/joules and temperature to whatever gives them the best experience.
None of the above is wrong. IMHO: all three are valid approaches to TC vaping.
As expected I find that my dual coil builds require more power than my single coil builds. While I generally vape at a mundane 380-430F (with the correct wire setting for the wire I'm using), there are times I like to turn up the temperature and open up the air flow and blow some clouds.
Every one is different so I would not worry much about the settings others use. Just adjust it to where YOU like it and the TC should give you a nice consistent vape every pull/draw.
Happy Vaping!