4nec2: Explanation of the parameters in the Main window

Hello,

I have doubt regarding the relation between Input Power, Voltage , Current and Impedance values in main window of 4nec2 .
The values obtained obeys the equation V = I*Z
but it does not obey the equation P = 2*V*I or P = 2*I^2*Z.
Am I missing something ?

Thanks,