1K done. Went to service center and only Verna among more than 50 cars

1.5l turbo pertrol SXO - love the attention this sexy Sedan gets. - mileage is a concern . Bumper to bumper I'm getting 4kmpl mileage. on highway max I achieved was 15kmpl. - the service centre mechanic said the mileage will increase on next service. Is this true? - idle start stop doesn't work 40% of the time. And I still don't know to manually turn off the engine with everything else running. - power and comfort is top notch. AMA