This perspective was given by my brother too when we were deciding the car, and based on this only we went for swift earlier. But practically driving a car with 9 Kmpl and 11.5 kmpl gives huge difference. Our Hatchback use is roughly 20 - 25k kms per year, so if we go on higher side the following calculations will give you the difference:
25,000 / 9 = 2,777.78 lit
25,000 / 11.5 = 2,173.92 lit
So 603.87 lit or @ Rs 115/ lit = Rs 69,444.7 per year difference only on fuel cost.
Also if you include the difference in maintenance cost, additional taxation, and higher depreciation the total additional impact will be more than 100K year for sure