If the HV curve did nothing but warn people that they are operating in an area where they need to be absolutely spring loaded to reacting to an engine failure, then it has succeeded. Spring loaded means - knowing all the various symptoms of the failure, knowing what you're going to do ahead of time - i.e. where you're going to go, how you're going to try to do it, and so on.
if it does that, then it's succeeded.
For those flying helicopters with more than 9 seats, it also means that the authority is expecting a higher level of safety from these helicopters, and that it's a limitation. You simply must not fly there to put all those bodies in danger.
Darkhorse - not that familiar with the 205/UH-1 charts. I'm surprised the military one is slightly smaller however!