I think people should take another look at First Principals post because it is the most sensible I have read. The 75ltr/min figure was what the pilot planned on, there is no mention of what the inflight figure was. From my point of view the report is all about being aware of how much fuel you actually have before departure and being aware at all times how much is left. Who in their right mind relies on the fuel gauges of light aircraft anyway?
The planned fuel consumption, the electronic gadgetry and the fuel indication were probably in close alignment with the expected endurance remaining
All of that points to the fact that the assumptions made were obviously incorrect. Unless there was a fuel leak somewhere, if the pilot overestimated how much fuel was on board then all the other assumptions are incorrect. The electronic wizardy is only as ggod as the information put into it. It applies to airliners as much as light aircraft.