Purchase of land from the market municipality - Internet guarantee, land area number, financing....

Then you have to check (have checked) exactly what he says about the above points:

§ 19 IV sentence 3 Baunutzungsverordnung:
"Deviating provisions from sentence 2 can be made in the development plan."

However, this must also have been done accordingly – silence of the development plan on this is not sufficient, because then sentence 2 applies, see above.

Request the finally adopted development plan!!!
The municipalities may have published it online.

So you are not only building a single-family house, but a mixed-use property with a commercial unit and a residential unit?
I don’t understand that now...

A completely normal single-family house in which a quiet business is operated (office in the basement) - hence the requirement for the third parking space.

Then you have to check (or have it checked) what it exactly says about the above-mentioned points:

§ 19 IV sentence 3 Building Use Ordinance:
“In the development plan, provisions deviating from sentence 2 can be made.”

But that must have already taken place.
Look for/request the finally adopted development plan!!!
The municipalities may have published it online.

As I was told by phone, this exception does not apply, otherwise it would be stated in the development plan. I am requesting this statement again in writing. In my opinion, it would actually be the opposite: There is no mention of a restriction of the Building Use Ordinance - therefore it applies.

In my opinion, it is actually the exact opposite: there is no mention of any restriction of the land use ordinance - therefore it applies.

Yes, I see it that way too.

However, as a precaution:
The municipality can change the development plan at any time (i.e. possibly revise it).

If the basic principles of the original planning are not affected - for example, if it is changed from a residential to a commercial area - the Building Code provides for the "simplified procedure" and some procedural steps are omitted or shortened (see Section 13 of the Building Code).

Nope, you are building a single-family house with a finished basement - nothing more and nothing less. That means the third parking space is off the table. I don't see any commercial unit. Once again, be flexible. What happens to all the "single-family houses" that have two parking spaces and where someone considers becoming self-employed - even if it's just the part-time mom who suddenly starts selling Tupperware or Thermomixers? Immediately create a third parking space, otherwise dismantling or prison!!!

Nope, you are building a single-family house with a finished basement - nothing more, nothing less.
That eliminates the third parking space. I don’t see any commercial unit.
Again, be flexible.

Well, I can only say what the contact person told me on the phone - and he says: 3 parking spaces. I have no idea...
The whole thing is defined as "per non-disturbing commercial operation" with "0.5 parking spaces per commercial operation." And of course it’s rounded up.

What happens with all the "single-family houses" that have two parking spaces and where someone thinks about becoming self-employed - even if it’s just the part-time mom suddenly selling Tupperware or Thermomix? Immediately create a third parking space, otherwise dismantling or prison!!!

Well, that’s basically what I assumed - anyone running a nail studio in the basement obviously has to provide and keep parking spaces for customers. That makes sense. Just not with the then quite low floor area ratio...

I’m curious when a response will come in.

Are you tense? You could easily pass as a civil servant ;)