Yes, and you can see, WHEN oil is in one grade alone it's temperature recommendation / usage is different as compared to it's mixture in Multi-grade.
The Spread b/w Temp. limits reduces in multi-grades. look SAE30 vs 10W30 vs 5W30.
And as you see 1st snap, 10W-30 covers our winter. It should give good mileage in new vehicles. 10W40 better than 10W30 and 10W50 (all season good).
Whose 10W40 is good ????? Mobil Super, Castrol Magnatec, Shell HX-7, ZIC A. I think these are known providers.
for very old with worn rings should go for higher viscosity to cover the gap with oil to save fuel/CNG leaks to crank case.