When measuring the duty cycle the N75 Valve using VagCom, What does the value indicate?

Is it the measuring the actual position of the valve? or the output value from the ECU to the valve?

Mine seems to be reading only 60-70% when the boost pressure isn't meeting the requested by almost 0.2 bar

Would this indicate the valve is faulty, or the ECU is only giving the lower value to the N75 due to other data from the engine?

Cheers

James