I'm not completely sure, but I think you get the "change oil" alert at 7,500 miles. I'm not sure about this either, but I think you can change this alert to something else as well. 'Comments?
You get the "change oil" alert anywhere between (roughly) 5K and 10K miles depending in severity of service and driving. Towing a lot, you'll get it quicker. Smooth 60 mph highway driving empty, I've seen it go longer. They're calculating that somehow, not sure if it's actually based on looking at the oil or just hours/miles/power requested/boost or something.