I now have 3934 miles on my Edge oil and it has been about 7 months and my DIC says I have 31% oil life left.
Doing my calculations, I have about 3 more months to hit 5701 miles, at which time my DIC should be at 0%.
I intend to send a sample to Blackstone Labs for analysis. We will then see if the "dipstick warrior" is right !
Since I have retired, and now only work 2 days a week (consulting), my mileage has gone down and my short trips have increased. I used to see 6500+ miles on an oil change, now more like 5500 miles.
I have been thinking about just doing a sample at 0% and waiting for the oil analysis results.
I know I will have oil life left, because I have a 1998 and the OLM is based on 10,000 miles maximum, later years GM went to 15,000 miles maximum. So, I really am changing at 33% oil life left.
I feel like it will be good news. I already bought some more Castrol Edge while it was on sale. If it is good, I could run the oil longer. If there is no improvement, I may go back to Mobil 1 and save the Castrol Edge for my daughter's car (a Malibu Maxx), she does a lot of highway driving and I am running Mobil 1 Extended Performance for 15,000 miles in her car now.