I don't think the ship actually displace 45000 tons now, unless it is ballasted for stability. 45000 tons is supposedly the light condition displacement for the completed ship. The ship is likely still missing several thousands tons of equipment and fitting.
This may be an optical illusion. But it seems to me 017's boot top is higher on the ship's side then Liaoning's, and closer to the bottom of the sponson. This suggests 017's underwater hull likely copied Liaoning's geometry, but the equipment, fitting and designed stores are sufficiently different in weight that the new ship is expected to have higher displacement when completed and thus sit deeper in the water.