Chambudzi, I have had to do that in a -400 (although not as low, 'cause we still had a long way to go - N of Nikolayevsk), and speed up and cycle the speedbrakes to increase hot hyd fluid flow through the fuel/hyd tank cooler. Didn't seem to have much effect later on over China, though.
I'm sure fuel low temp is stored in the hard memory of the 777.
A question for the kerosene expert above: does increased flow rate in cold-soaked fuel cause a greater propensity for any water particles in suspension to form ice crystals upon hitting the face of a filter or pump casing? ie: if the EEC's commanded more thrust and hence increased fuel flow, could this cause instantaneous increase in ice crystal formation?
I have had it explained to me once that a filter face can cause a multitude of microscopic points of decreased pressure perpendicular to the direction of flow, much as we all learned during fluid dynamics with a varying pipe diameter.