While the fuel economy figures for the gearboxes should be within the same ranges you listed, final figures boil down to many variables, such as driving speeds, traffic conditions, etc. In our experience of running Hyundai/Kia cars, IVT-equipped models are more efficient than DCT-equipped versions. The lower fuel economy is also a function of the DCTs being paired with turbo-petrol engines. They are more sensitive to driving style than naturally aspirated engines.
As for your question, an IVT delivers a smoother experience in city driving. A DCT can, at times, feel jerky at very low speeds. However, if it’s performance that you seek and will be driving on highways often, a Seltos turbo-petrol with a DCT makes for a more exciting choice, despite the slightly lower economy.