A 0.5 ohm coil will hit 4 volts at 32 watts.
I just tested my subox running a 0.4 ohm coil against my voltage calculator and it's pretty much spot on from what i can tell.
Regardless of what is displayed on a mod just start on low watts and increase till you find your best vape.
All mods imo perform slightly differently so what works for you on one device won't be quite right on another.
Maybe a better question would of been. "I've just read this info, is it correct? "
Other than a battery going into meltdown in pretty sure there's nothing vaping can throw at us that's even vaguely as dangerous as tobacco and I bet you didn't worry about that.