and the cost of the KPI's themselves
I actually don't know the answer to that, but I think it is pertinent to know exactly what pecuniary benefit is secured by those management pilots with a keen interest in fuel conversation, for the sake of transparency.
Of course one might assume that their actions are motivated by higher purpose alone.
One might also ponder whether the lack of a dual aisle twin to replace the 767 left Qantas with more single aisle 737 than was optimum.. Has that meant a consequent increase to the fuel burned, whether engines to lift them or APU to cool them? Carrying a similar amount of passengers spread over more air frames might be another own goal?