Your old Olds must have been reincarnated as our kids’ old VW 2002 Jetta. At about 80k miles, we just routinely dumped a quart of oil in at every gasoline fill-up. Sometimes it took 1.5 quarts if it was off the bottom of the stick.
I used to buy oil in the paper containers with the metal lid in Missouri around 1970 for $0.25. You’d push in that piercing spout and your hands would always smell of oil afterward. Today’s youngsters with the plastic oil “cans” and the screw-off cap — sheesh, they don’t know how good they have it! Of course, who has to add a quarter of oil between changes these days anyway?
Oh yeah, I remember that piercing spout. After you’d emptied the can and turned it upright, oil would drip down between the outside of the can and the spout, making a mess if you weren’t prepared with a paper towel to catch it. If the gas station didn’t have a spout like that, they’d give you a paper funnel.