DeltaFree,
Your logic is circular, neat and precise, and unfortunately wrong.
You say "a helo arriving close to the ground will produce a pressure build up which make the rotors more efficient reducing its rate of descent. So yes you get an increase in pressure."
Why not say, with equal evidence and equal physical data, "a helo arriving close to the ground will produce a little red demon build up which make the rotors more efficient reducing its rate of descent. So yes you get an increase in little red demons."
There is no pressure buildup. That is the old pilot saying, like an old wives tale, told 10,000 times, so it must be correct. Were the pressure higher below the helicopter close to the ground, it would be measurable in many ways, such as your altimeter. No measurement shows higher pressure.
I am sad to see the thread last this long, and that the 40-zillionth post starts off where the first did. Oh well.