Understand is that it’s an efficiency formula based on 3+ factors. Not raw separation rather who the pass is going to. On any given play a QB can miss an open WR and throw a pass to one more covered. My understanding is the chart only starts tracking who was targeted. So many factors are left out, including time to pass, OL-clean pocket, QB in/outside the pocket. This isn’t a complete analysis, probably only guys who study film can understand the whole scope of things.