That chart is a really rough guide. Many of us have been vaping 9+ Watts as a norm for several years. It's more like state of vaping 2010. 1.5 ohm on single batteries & VV/VW are hardly exotic these days.
Granted, different liquids play well at different power levels, and starting down around 7 Watts is fine, but the warnings on the bottom starting at a whopping 8.7w are a bit over the top, and it would be pretty rare to hear someone actually saying that vaping 3.6w is in the sweet zone.