Not to negate your point but just to negate it slightly. It is only generally reflective and their can be outliers.
One year around 2019 or so our good friend Bruce became obsessive about the point you have posted. And was confidently discounting some top 8 teams and said they would fall out and that we were going to make it as we had a better PD and none of it played out. We missed the 8 by memory while having a reasonable PD and Knights or someone snuck in with a negative or very low positive number.