Thanks Con. as I said earlier. correct me - Does the higher transition make your workload harder ?
Exactly the opposite. Setting QNH before or after you get busy is a good thing. Those wacky departures in the UK where every time you reach for a knob you get a radio call are spring loaded for missing that 4000 feet (or whatever) low transition altitude. Likewise, on the way down, if you miss the change to 996 hPa, you don't have much time to catch your mistake before you get a GPWS (or, so I'm told
).
A friend of mine from the UK is dismayed that many U.S. departures are now simple vectors, e.g. runway heading, maintain 5000 feet. I guess he still does NDB holding and stuff like that on his instrument check and doesn't like the simplicity.
If you have to change the altimeter more than once below FL180 in the U.S., it's a tweek since you've already set QNH and even if you miss a call, you'll usually be closer with the arrival ATIS value a hundred miles out than with QNE (sometimes in the NE U.S. you will be below FL180 a hundred miles out to get under another airport's corridors).