That's the worst advice that anyone can give you for a car with such mileage. If this car is kept with care as you can judge it by analyzing the overall condition as well as the drive, the recommended Engine oil grade is 5w30, and also use Fully Synthetic and not semi-synthetic ones. First of all, they advised you to use the wrong oil grade for your car, and secondly, they suggested you use the semi-synthetic (Petron).
So, use the Engine oil grade 5w30 Fully synthetic of any reputable brand available in the market.
I hope it helps.