E-field values (CST MWS)

I want to know the E-field (nearfield) value at a certain distance from an antenna. I place a probe at the desired point. I use a Gaussian pulse as excitation signal, but 100mW amplitude (instead of the default 1W). The probe value at the desired frequency and the 2D results (at approximately the same point) are very different in magnitude, and they are equal to the results when using the 1W excitation. The probe signals peak values are also different to the other two, but they do change depending on the input signal amplitude. Any idea of which one is the value I can consider to be correct?