Well you can consider me one of those uncles buying from Tesco during promotions. It becomes much cheaper and very worth it IMHO. If you buy Mobil 1 FS for rm140/4ltr during the promo, and use it for 10k kms, it actually becomes even cheaper per km than using semi-synth at rm80-90 that usually need to change at 5k kms. To me those are good enough already, my cars still running nice and the metals inside still look very clean, hence I don't feel the need to buy such expensive ones.