we are in the final stages of planning our single-family house and the plan is about to be submitted to the municipality. We also already have a construction company lined up that could build the shell including the roof this year.
The house will be built in a new development area with the corresponding development plan. Due to the tight schedule, the goal is to carry out the building application through the exemption procedure.
In post #3 you sound as if it is practically about the difference between a basement protruding from the ground on average one point forty or one point twenty, where you could meet an older version of the legal basis and only exceed the smaller dimension. Otherwise, it would be helpful if you had linked this thread with the presentation of your house yourself:
Your problem is that with the "exemption" you are in a way declaring on oath that your construction project complies with the specifications of the development plan without the need for any exemption. If this is the case, you can calmly face a later inspection (spot check or denunciation) and your building project is considered as uninspected but legally equivalent to an approved building. If this is not the case, a subsequent check would reveal a violation and your house would be considered not an approved but an illegal building. "Arguments" for mitigation of penalties won’t help you; I see you standing before the choice between two paths: namely legal certainty through a proper full building application procedure (including here probably applications for exemptions). The latter I expect to be denied as I see no justified hardship.
A further round of reflection on your draft, which in my opinion has no shortage of potential for improvement, seems to me like a gift from God (and in Bavaria also from the Holy Mother Mary), for which you should light a big candle in thanks.
I also see a spirited quick help to achieve undisputed regulatory compliance served on a silver platter: namely by simply forgoing the basement under the living room and re-purposing the basement so that maybe brewing also happens in the fitness room or exercising also happens in the technical room.