The Amber Fuel caption, (there is only one), is operated as a mathematical sum of total fuel remaining and comes on circa 70 - 75 kgs total fuel. (How much did the AAIB find?).
The fuel was found in the MAIN tank by AAIB!!! The caption FUEL is related to the supplytank! It normally comes on whenever the amount of fuel is arround of 36kg for Supply1 or 32kg for Supply2!
skadi