Quite right Wholigan.
There is another, easier option for high level airfields, request QNE. QNE is your altimeter reading with 1013.2 set. Thus ATC would give you the number of feet you would see on your altimeter on the ground at the airfield datum with 1013.2 set in your subscale. I had to use that at Entebbe when the QNH was outside the range of my altimeter.
Neppie
