I'm sorry to bring up an old thread but I feel obligated to reply to this thread.
I would STRONGLY recommend AGAINST going to 0%. It's my understanding that GM claims 20% on the oil life. I do know OnStar will flag 'time for an oil change' starting at 19.9% with their On Vehicle Diag and also email the dealer if you subscribe to Dealer Maintenance Notification. This is OnStar, a GM owned company telling you to change the oil at 20%.
As a dealer, the only reason they would tell you follow the oil life monitor is because they are repeating what GM says. If they are half as good as they should be, they would strongly recommend 5-6k miles between oil changes.
I can't tell you how many 4 cylinders (2.2's) that have been in service for cam actuators and timing chain components, being all tensioners, guides and even new chains because the actuators get clogged up with dirty oil from people following the oil life monitor. GM is paying these claims with no questions as of now. There's also a reprogram on the PCM that shortens the Oil Life Monitor at the same time these are done.
The reprogram tells me that they know this is a problem but they have commited so much and so hard to the Oil Life, they have no choice to stand behind the concept.
Something else worth mentioning, starting with 2011, all GM vehicles with a gasoline engine require a synthetic blend motor oil such as the AcDelco Dexos1 oil. This was an effort to help extend the oil life and keep the oil cleaner through the extended drain intervals of the oil life monitor.
Now .. I'm not going to tell you that you shouldn't follow the oil life monitor, but I will tell you as one who is in the know I will not. I will change the oil in my little Sonic at around 5k miles, just as I do in my 2011 Tahoe. FWIW, my Tahoe does get the Dexos, but the Sonic gets Mobil1 (solely because of the turbo).