Base plate incorrectly positioned

Sometimes you just have to leave the crap where it originates. Compassionate people often find this difficult. I estimate your costs to be higher, because you will live with a solution that “hurts” you.

Why is the building authority actually coming? At our neighbor’s, the house is too far back, no one has cared about that so far and no one has checked either ...

Why does the building authority actually come there? With our neighbor, the house is too far back, no one has cared about it until now and no one has checked ...

In our district in Bavaria, someone from the building authority always comes and checks pretty early whether the measurements from the building permit have been adhered to.

I would be interested to know how the original terrain was then stored, because the allowed distance results from the building height to the original terrain ... which no longer exists because it has been filled up ....

Even if I "didn't care" about the position of the house, I would still insist that they correct it. Whoever messes up has to deal with the consequences; this has nothing to do with "humanity" but with "doing the job right." You demanded and paid for a service (or will pay for it), so the good sirs should also do their job properly.

Additionally, you say that the 20cm would bother you. If you are already aware of this now: How do you think you will regret in 10 years that you didn't assert yourself now? Leaving aside the fact that a change request at the building authority also takes time and may cause new problems/costs. What do you think the structural engineer would say if you transfer €10,000 too little and say "oops, I made a mistake" – do you think he would think "oh, the €10,000 does bother me, but for human reasons I'll let him have the discount"?

He wants his money for the service he provided and you want the service you agreed on for your money. No, no, I definitely wouldn't accept that.

You’re not satisfied with the foundation slab itself either, if I think about your other thread. So there are already two aspects, location and quality, that rather speak for "doing it over." Or can the quality simply be repaired?