Hey SS - I am quite prepared to believe your knowledge of the EC135 type is greater than mine. That said you don't seem to fundamentally disagree with my overall point.
That being when the red "low fuel" warning alarms you have this 8-10 min window which as you point out is dependant upon the specific model.
As the AAIB report suggests
the No 1 supply tank (left) contained 0.4 kg of fuel and the No 2 supply tank
(right) was empty.
Are you suggesting he didn't have his 10 minutes?
Apologies for the missing ref; I'm simply using the information Eurocopter themselves give
here