Hi Faustin
It is recommended that you calibrate the setup with the current sensor. Even if you end up modelling the current sensor very closely (which by itself is quite challenging), you will experience some inaccuracy in the results when you use the actual sensor with these calibration constants, as each sensor is different- there will be some gain/phase error from one sensor to the next (even if it is the same model and specs). Is there any reason why you cannot calibrate the setup with the current sensor?
Regards
hmani