Utilize the plot ratio for new construction, build over the terrace

Hello, I have a plot of land (610sqm) and now the planning for a single-family house with a granny flat is starting. I have already read a bit about the topic of building regulations (especially floor area ratio). In summary, I have understood that in my case a floor area ratio II of 0.45 and an I of 0.3 applies. Thus, I can build 225sqm, but the main house with terrace may be no larger than 183sqm. I am trying to "squeeze out" everything because I actually only want to build the two full floors and keep a roof conversion as a last option open. In almost all examples now, the house with e.g. 10x14m already amounts to 140sqm and then the terrace(s) add assumedly another 40sqm. For me, a main house with 140sqm would be too little, ideally it would be 180sqm per floor. But I do not want to give up two terraces either. My question now would be whether it would make sense to cover the terrace with an overhang starting from the first floor. I find it hard to describe, but if the terrace is counted anyway, then one could build e.g. 140sqm on the ground floor and only 180sqm on the upper floor. I have seen that on very few pictures so far. Mostly it was declared as an urban villa, although I could not find a name for the covered terrace. Can someone help me, or disprove my idea by showing me that it is a stupid idea ;-)

Floor area ratio I of 0.3 refers to the residential building. In most development plans, you are allowed to exceed the floor area ratio I by 50%, that is from 0.3 to 0.45, for this floor area ratio II. This exceeding applies to ancillary facilities (garage, terrace, footpaths, etc.) Please check which floor space index you have according to the development plan.

I suspect that you will have to part with your exceeded plans (360 sqm residential development) due to the floor space index ;-)

Hello. No, a floor area ratio is not specified. Only the eaves height of 6.5m and the ridge height of 8.5m.

That means 2 full floors are definitely possible, an attic would also be possible with dormers and a cross gable, but as I said, I actually don't want that.

... the terrace is always part of the main house, so also floor area ratio I. That is precisely my "problem", therefore my question is whether it helps at all if you "extend" the house over the terrace to have more living space. The terrace is counted anyway, if there is a living space above it, at least it is not used up just for the terrace.

I suspect that you have to give up your exaggerated plans (360 sqm residential development) because of the floor area ratio ;-)

I perhaps should have said something about my family situation, because in my opinion my plans are not that exaggerated.

We have 5 children, and the granny flat is supposed to replace a 100 sqm 4-room apartment previously used by my parents. Accordingly, it should be at least 75 sqm with 3 rooms and a kitchen.

I hope the standards of ugliness of the overweight house above were not just borrowed here or are meant to surpass them:
https://www.hausbau-forum.de/threads/modernes-bauhaus-viel-glas-170-qm-eg-og-derzeit-in-phase3.38031/
https://www.hausbau-forum.de/threads/architektenentwurf-planungskrise.38915/