212man,
I am familiar with the more comprehensive H-V diagrams to which you refer. Figure AC 29.79-2 shows three different ways to present H-V data, the most simplistic of which is the one commonly used today where the H-V avoid area is fixed and accommodates all gross weight/density altitude conditions at up to the HOGE weight (for all altitudes and temperatures within the certification envelope).
I understand your desire for a more precise determination of the H-V avoid area. But H-V testing is a risky business, and one could argue that exposing the test aircraft and crew to the number of engine cuts necessary to develop a more comprehensive H-V diagram is not worth the risk. It is my observation that more parts are bent during H-V testing than during structural demonstration testing, including hard landing tests where the aircraft is flown into the ground at a pre-determined airspeed and ROD.
HT