Bro it totally depends upon specific pump be it Shell,Total,Pso or whatever.
It's better to choose pump after your own experience.
There is a Shell pump opposite Butt sweets Garhi Shahu.It gives me best mileage in my YB100.Also a BYCO pump(but its far away from my house),also gives good mileage.
I prefer Total petrol pump Link road due to good mileage but it is 3kms away from my house.
That's why I usually refuel from PSO which is near my house but it's just fine. (Laziness) lolzzzz