As well as offering far higher levels of accuracy than the standard DW12 loadcells, the bf1systems parts come with standard calibrations for front and rear parts, meaning that if a part is swapped on the car, the team know that the new part they will be fitting to the car will contain the same calibration, meaning that the calibration in the logger does not need to be changed, saving the team time.
Calibration is setting the output (for a given input) of an instrument equal to some known standard. Instrumentation must be adjusted and checked to ensure that data is accurate. If data is to be recorded, good calibration of the recording equipment can be time consuming. (Source: Race Car Vehicle Dynamics)