But when you say "goes 10x further per [unit fuel]" you're talking about it the other way! I.e. this one gets 110 km/L, 10 times more km per liter than your car that gets around 11 km/L.
If instead you're comparing 9 L/100km to 0.9 L/100km, that's not talking about how much distance you get per liter, but about how many liters you use per distance, i.e. the rate of fuel consumption. Of course, they're equivalent ratios; it's just a reciprocal.