Henry Crum, catch 21...and others.
I do think you, along with others have worked out a very plausible start point for the error that led to the flame outs. We still haven't a clue why no actions were apparently taken to respond to the many warnings of the worsening situation.
Scuffers, it most certainly is not the standard practice to land with less than MLA fuel, it's not something that can be covered up. The police crew would be aware of it (they are an integral part of the challenge and response pre-landing checks and the refuelling process, and it would require collusion to falsify the tech log records....not something the police are going to do. If it did land with less than MLA, I would expect an MOR to be raised and a degree of de-briefing from management to take place. We still have no evidence that Dave knew he would land with less than MLA though I agree that the flight time suggests strongly that would be the case.
For those that missed earlier posts, the EC135 training manual indicates the fuel system can be up to 6% fuel quantity in error under normal operating conditions. This does provide a margin that means we may never know exactly what figure were displayed in the cockpit.