Answer:
No, unfortunately this is not possible.
The program concept of RF‑CONCRETE Surfaces is designed in such a way that it is always necessary to place the reinforcement on the top and bottom layers.
If necessary, you can try to concentrate the individual reinforcement layers in the center of the surface, if necessary. However, make sure that the individual reinforcement layers do not "touch" each other. Otherwise, an error message appears. See Image 01.