I used to buy engine oil from Tesco for years. Tesco is worth to trust than spare part shop. I am glad that Tesco and AEON Big importing engine oils and sell at reasonable price despite of main distributor in Malaysia and Singapore selling at crazy price.

Sometime Giant Singapore offer at Shell 5w40 @ SGD32.90.

Please survey overseas market e.g. amazon, then you will realize that engine oil is very cheap in western countries and Tesco has good margin when us selling @ RM129/4L

For example, Mobil 1 Extended Performance 5W-30 Motor Oil - 5 Quart only USD11 after rebate at USA now

We could google anything to learn. It is not wise to believe that paying more for better quality.

Be a smart consumer

Good luck