Unclear development plan E+D or II

The architect believes that a second concrete ceiling would not be possible with II. I see this somewhat differently, as otherwise the development plan would not offer the choice between EG+DG or II. With EG+DG, the knee wall is also higher at 1 m. With II, the knee wall is only 0.5 m. In my opinion, the basement does not count as a full floor, as nothing is stated about this in the development plan. The responsible authority has not yet been consulted.

First of all, many thanks for the competent explanations.

Why a second concrete ceiling? What is it supposed to support?

The basement is, in my opinion, not considered a full storey, as nothing is mentioned about this in the development plan.

This is not regulated in the development plan, but in the state building code. If a basement protrudes on average 1.40 meters above the surface, etc. That would at least give your development plan some logic. Unfortunately, in my opinion, that would exclude your house. Do you have a slope so that it is explicitly expressed that way?

The architect says that a second concrete ceiling would not be possible at II.

The development plan does not care whether your ceiling is made of concrete or wood. It mainly regulates the building structure as it is seen from the outside.

At EG+DG the knee wall is also higher at 1 m. At II the knee wall is only 0.5 m.

You can do that with 1+D because the building structure then does not become so tall overall. That is also why a higher roof pitch is allowed. In the end, both reach a maximum height of 10m.

We have no slope; the property is completely level, i.e. the basement does not protrude from the ground.

Just for your information: The floor area ratio is 0.35 and the plot ratio is 0.6. Does the basement actually count towards the plot ratio? It is actually not living space. The building plot is in Bavaria.