My AFM although seemingly working fine, was actually Faulty and caused some mad Pinging when I was getting a tune. (SAFC2)
Swapped in a replacement and all good.
Try a different AFM and see if the results are the same...
Might have to just keep a record of what was on it compared to what is on it.
I have a white faced cluster with approx 100,000 less than my cars and was considering doing this.
The way I see it, You save $$$ by getting the cheaper one and you save $$$ on fuel.
Supposed to change them every 40 to 50,000km. It all adds up.
Whatever Flower Girl.