Keep in mind that the engine manufacturer usually provides the power output/fuel flow tables with an average of the 10% of accuracy. This means that a 10% of error is still admitted.
That said, always check the performance tables for the specific EGT you should set to get the proper readings (for example, many tables report the fuel flow at peak EGT). This means that you must lean the mixture properly.
← The fuel consumption is different that the one reported in the performance tables