I've driven 7k since october 2019. I got 10w40 on 5000 kms. I have observed that the car is averaging 15 kmpl being used at home 1st/2nd gears. Previously if not more it was doing 17kmpl.
I might take the risk of using caltex 0W20 or 5W-30 in the next oil change. And check what happens. Idiots at suzuki used a rs.200 oil filter in my Alto and said this is okay. No problem with the warranty.
I'm not stressing out about it will probably take my own parts/oils in next service and tell them to use my parts. Done 7500+ uptill now. Plan to change gear oil aswell on the 10k service interval