Hey guys... Thanks for all your posts on this topic! I appreciate your knowledge and advice.
My Buick does indeed have an OLM. At around 3k on the oil, the OLM is showing 50% currently. The car has had a fairly easy life in it's first 15 years as it was garaged and maybe driven 1-2 times per week by a previous family member. Since I have had the car, I've put on roughly 25K miles and have completed numerous repairs. (Intake gaskets, Manifold, plugs and wires, gaskets, flushes, hoses... almost everything including the PVC is new.) The car has been awesome and If I keep it at 65mph I can get 30-32mpg on the highway.
Prior to my ownership, the engine mainly saw two-oil changes and I'm pretty sure it was vanilla PYB or conventional. I've had good luck with Supertech and have never used a high mileage oil in the engine. I'm guessing if I go by the OLM... I'll see maybe 5-6k on the miles for the OCI.
When I had the engine apart for repairs, it was very clean inside. Soooo... I suppose the QSFS is just finding a way out the tailpipe for whatever reason. I'll keep a watch on it.
I may do another run on the Supertech to see if there's consumption. The car has lived 95% of it's life in AZ. At this point, I may limit my OCI's to 5k. I never thought about 3k oil changes because the engine is a 3800 and not a stressed high HP engine. I'm pretty sure most any modern oil is far better that what it was fed 21 years ago!
Anyhow... I appreciate this forum and all of your post guys! Thank you!