Gaspath, I am very interested to know how you believe the you know the engine FMU's responded to the throttle command. In my experience, you only can tell something like that by studying the QAR data.
As the FMU's
1) have no external moving parts and
2) would be covered by the engine fan cowls (and latterly by a few tons of earth) I'm sure that your ability to see the unviewable would be of service for many accidents.
To all those who are singling out the engines for sole fault on the basis that both failed simultaneously, I invite you to remember that the the item that links both engines and their control is the airframe and the flight control electronics.
When two engines 'fail' simultaneously, the cause is very likely to be external to the engine.