It's a solid metric; it definitely corresponds with how I'd rank these teams as well. Us, Boston, and Toronto are definitely a tier a above Cavs Spurs Heat and TWolves
It's a good formula. I'll give one small asterisk for the Cavs and say that it's hard to know whether they are even trying right now. I'm not sold that they can just turn it on in the playoffs, but it's at least possible.