DERG
I may be becoming senile, but wasn't it all about increasing skin temperature i.e. TAT, to increase the fuel temp ? well if my memory serves me it is on a 737 anyhow, rather than as a function of increased power/heat exchanger.
The difference in power required to maintain the higher speed will be minimal, the difference in temp I would suspect not be enough, but maybe tangible. This is obviously more viable at lower altitudes where you have a somewhat larger window of airspeed available to increase to, shurely not the case here on a long flight.
Anyway, Shirley, if everyone else was descending, either there was a problem with the fuel temp measuring on MMM or everyone else was in a different bit of air, as I seem to remember the report stated the fuel temp remained within limits for the duration of the flight.
jumbojet, did any of your colleagues note the fuel temperature they experienced and whether it differed greatly with the FDR readings in the report pertaining to the accident aircraft. Perhaps a tech problem that is being missed.