Subtle difference in the UK:
Excerpted from a list in one of the documents you linked:
The following hazards can and do result in a level bust:
• Low transition altitude particularly where initial Standard Instrument Departure (SID) clearance is to a flight level.
• Periods of high cockpit workload – take-off and climb, SIDs particularly with a stepped climb.
Those low transition altitudes in the UK combined with complex departure procedures are absolutely spring loaded to screw up in my opinion. I know it's a case of NIH, Not Invented Here, but I would hope that someday the UK will raise the transition altitude to something that is more user friendly to large aircraft. And, have more 'maintain runway heading or as assigned, climb to FL200' procedures. We promise we won't level off at 2000 feet next time.
In the U.S. many pilots choose to never fly internationally and often the training is based almost totally on domestic procedures.
Usually, by the time you get to 18,000 feet things have calmed down and its unlikely that you would both miss the transition so what's the problem, right? In recent years the feds seem to have required more realistic sim training for those of us who fly internationally.
Over the years I've seen many procedures for altimetry approaching transition level or altitude.
One procedure is for both pilots to wait until transition altitude to switch to QNE. Another is for both pilots to set QNE when cleared to climb above the transition altitude. And, a third is for one pilot to set QNE when cleared above transition altitude and the other to stay on QNH temporarily just in case ATC asks for altitude passing (and not level passing
).
Add the fact that some procedures include the standby altimeter which in the past may or may not have been 'corrected' (I think it means they didn't work well up high). And most autopilots will level on the captain's altimeter but with some procedures it's the pilot flying's indication that the autopilot sees.
And, in the case of a low transition altitude with and initial SID clearance to a flight level, for a while we were able to optionally set QNE before departure as a 'strategy of threat mitigation'. Then someone observed that our performance data and noise profiles were based on QNH altitudes.
Anyway, I'd rather be 400 feet off on the altitude passing call to ATC than on the level off so I tend to be proactive about setting QNE and QNH early.