Impedance changes with input power in layout simulation (ADS)

Hi...

I'm doing multistage rectifier....
During schematic simulation...measured output current (I) and voltage (V) are good...(all the impedance/resistance value are remain the same for different input power). However, the same circuit (same component but now with the layout)...the measured output I and V showed that the load impedance now changes based on input power...the higher the input power is, the higher the impedance value...

I'm doubt about how to define the efficiency of the circuit?
based on measured I and V or stick to original resistance value...
FYI, the output is the component of 200kohm resistance.

thanks