As a slight thread drift...
This miss the transition change over is actually quiet common when the sop is to do it at transition. the more modern FMC machines you can program a warning so the computer will remind you.
If you do it the British way when your cleared, its over 10 times less likely. And this isn't just a Brit having to change its also colleagues who were initially trained to change at TA/TL. I will admit I have done it as well when working at a company which had it as a hard SOP it had to happen at transition.
While using the UK method I have had a stop climb/decent maybe 3 times in 15 years which required a resetting of standard or QNH. Only one of them resulted in a level bust which was going to happen anyway when your descending at 2500ft/min and your given 800ft to level off. It was 1015 QNH that was set so it captured early and still over shot by 400 ft thankfully the cabin was strapped in.