How much living space? How many floors? Holiday home in a special zone

Good day, we are planning a holiday home in a special area (Lower Saxony) with a single-storey design.
Our idea…
- Flat roof
- 3 floors:
1. Basement on a slope
2. Ground floor
3. Attic
- Floor-to-ceiling windows everywhere
- Open staircase inside the house

We have submitted a preliminary building inquiry, unfortunately the result was very disappointing.

- Attic and basement may only have a room height of 2.15m.
- Attic and basement may not be used as living space.
- The staircase is open, it appears as if the entire house is being used as living space.
- Floor-to-ceiling windows in the attic and basement are not allowed, as it seems these rooms would then be used as living space.

We do not understand why we cannot design it as a recessed floor with a 2/3 rule and use the attic as living space.
Perhaps you have tips for us on how to redesign it to use all spaces as living space.

Development plan stipulations:

Good day, we are planning a holiday home in a special area

... but it seems they consider the municipal representatives, who explicitly designate the planning area as a special area, to be jokers.

We made a building inquiry, unfortunately the result was very disappointing.

No, absolutely as expected.

The attached excerpt from the structural provisions says nothing about the question.

The attached excerpt from the building regulations says nothing about the question.

These are the requirements of the development plan, it only includes these rules, no others, the development plan has only 1 page.

... but seems to consider the municipal representatives, who explicitly designate the planning area as a special area, to be jokers. No, absolutely as expected.

The area is a recreational area, therefore a special area.

Edit. The floor area and gross floor area amount to a maximum of 65 sqm according to the textual specifications. This establishes that the basement and attic heights are to be constructed as non-living space, hence the 2.15 m ceiling height.