I'm sure that (almost) all of the above is extremely valid and should be considered/implemented in order to minimise risk in the future. However, whatever happened to the relatively basic mental gymnastics that most of us use on a daily basis? My understanding of the extant SOPs was that Night/IFR final reserve was to be 30 minutes, about 85kg. So, the sortie commenced with 315kg of task fuel available which, at the historical burn rate of 3.3kg, gives 95 minutes of flight time.
I'm a bluff old traditionalist and in my world I would have imprinted 95 minutes on my mind before getting airborne. Any fuel warning, especially beyond the 90 minute point, and I would be going straight home.
It is extremely annoying to know that there was actually enough fuel in the aircraft to safely make it home and, for the sake of some (more ergonomically designed) switchery, we would probably have been left reading a GA occurrence bulletin. However, regardless of the technology, there is no escaping the fact that this aircraft was being operated at (beyond?) the limit of the prescribed procedures.
..... and before anyone shouts me down, I spend much of my life wondering about how many more minutes on-task-time I've got left in a very thirsty Piper Chieftain.