We have been getting this a lot lately. We have had a ton of folks deactivate the AFM to avoid oil consumption issues in their trucks. This review was just posted on Amazon:
"Used on a 2009 Suburban, that is substantially used for highway travel. Having the AFM disabled has not decreased fuel mileage whatsoever. This suburban was using oil due to the AFM (approximately 1/2 to 1 quart in 3,000 miles) and this is the only device made that can disable AFM without a tuner. After using it non-stop for approximately 4,500 miles - THE OIL USAGE HAS STOPPED - PERIOD! I just checked this morning and the oil has NOT budged. (2009 Suburban 36,500 Miles)."
We'll continue to monitor the results of our users and report back. We didn't test for oil consumption specifically, but you can check out more of the reviews here and here.
Best,
Adam