I've done another drawing to try to explain this. As pointed out earlier, there must be a step beneath but it can be smoothed out over a greater distance. The highlighted yellow area shows the additional space that this higher chassis gives.
Whether it passes crash testing is another matter.
After discussing about this idea on this forum it would seem that it is probably an unlikely solution but one that teams could still use as it is within the regulations. The cross sectional area of the chassis is still legitimate. To re-energise potentially detached airflow along the step beneath the chassis you could place a reward facing slot at the back of the front wing that is fed by the hole in the nose tip, kind of like an S-duct but for the underside of the chassis rather than the top.
Here is what I said about this design in my updated post:
"The yellow area in the above image highlights the potential that a higher chassis layout could bring. There is quite a significant gain in volume although whether this can be exploited is another matter. Another stumbling block about this design is whether it will pass crash testing as its shape is rather irregular on the underside."
What are your thoughts?