Bert (Sunova) has used stepped deck in the past.
This one is the Shroom from my 2016 video... a bit off topic of the Genration boards, but since you are discussing stepdecks....
Plus I think I see similar design work on the Genration instagram profile shot.
Doubtful the Genration has much concave in the bottom, since there is no wide tail to overcome.
The Shroom is a very interesting board with all sorts of things going on.
Note.... this is my hackers explanation of what I feel when turning my 8'3 Shroom:
I imagine Bert was trying to overcome the usual issues with wide tail boards, without any real hips or rail curve.
The deck has a massive concave and the bottom does as well.
They work with the step down rails give an awesome "bite" that truly
carves a snappy turn.
My cross section diagram is what I feel when applying the combination of concaves and steprail.
The pic shows the degree of step in the rail and the deep concave on the deck.