They are selling Pennzoil as an upsell !

If that's true then it's probably because it's cheaper than whatever they were buying before and many consumers probably won't really care as long as it doesn't void the warranty. Though pretty much any oil these days that has passed the API S whatever sequences is sufficient. The additive packages are almost always bought from a place like lubrizol who does all the testing and then suggests a basestock to go with it.

 

Isn't Coastal the one that ran into an issue with some of their 5W30 actually being 10W30 some years back? I don't know who makes that oil.