Firstly, checking the specs, MH370 was fitted with RR ('Trent') 892 engines. The charts are typical of many similar that I have seen for many years.

ALL charts above 20,000 feet (FL200) are presumed flaps up, since that is the maximum flaps extension altitude. In any case, it is extremely unusual to need slats or flaps at that high an altitude anyways.

Extending slats and flaps greatly increases drag.

Not sure what this question means...basically, the "LRC" chart numbers are to maximize range...they derive the best speed for an altitude/weight combination to provide the best lift/over drag coefficient.

The "Holding" chart are meant for fuel calculations when adding fuel for anticipated holding situations, during pre-flight preparation. Also, when holding, there are certain speed limits

*within *the Holding Pattern, and these vary by altitude...still the intent is to use the best lift/drag speed for your weight, and in cases where that speed might exceed the Holding Limit, you can ask ATC for a variance, to avoid the use of slats/flaps. (and the increased drag and fuel consumption).

Nothing is really "pinned down" at all....these are the performance parameters derived from the flight test results, used as guides for fuel calculations, again, primarily in flight planning. BTW, the onboard FMC (Flight Management Computer) also will proved the crew a real-time LRC speed, and other choices can be inserted to see how options (changing speed/altitude) for the present weight will affect final fuel at destination.

I guess the point is ( and I probably got a little technically deep, and long-winded

) that your endeavor of trying to find a set of possible range arcs for MH 370? There really are a vast number of variables, and the greatest unknown is....we just do not know what happened, and what sort of speed/altitude choices were made. (I say "choices" since nearly all the facts known so far point to altitude changes, which then rules out the autopilot continuing in cruise, with the presumption of all crew incapacitated).