Switch from Full synthetic back to blend.

[The Critic]

Could a car of today accomplish that kind of mileage or was simpler better?

Very unlikely.

 

[partspro]

At Jiffy Lube today:

View attachment 97089

Maybe Jiffy has changed or just the store near me, they NEVER had PENZOIL, just cheap Shell stuff my Buick Century just didn't do well with it, i think they underfilled also, now do VIOC new story, always checked dipstick even called out torque on drain plug, under car camera always took coupons even expired, set tire pressures etc