Thats why I am so confused, I do own a meter with duty cycle. I have the CD manual with the codes and all the diagnostic testing. I have become somewhat profficient at diagnosing my lambda control.
When I go CCW, I see my duty cycle go up, CW it goes down, just like the manual states.
For what I understand the Duty Cycle (in an ideal system) should oscillate between 45-55%, at idle and at 2500 RPM.
There is an acceptable 10% difference. ie. 40-50% idle and 50-60% 2000 RPM is OK
Mine normally oscillates at 41-48% idle and 49-57% at 2500 RPM. And those values were achieved "tinkering", just like your name.
Obviously all the inputs are OK, since I have no fixed duty cycles.
Except when cold, I get 50%, when it warms up it oscillates (which only makes sense, since closed loop happens only in a warm engine)