Surveying Services - Cost Differences

Which question?
I have not asked any question since post #1, after I realized that the price results from the fact that no official site plan is being created here.

That was not clear to me in the initial post (with questions).

Then I have probably wrongly interpreted the

Now I am trying to find out whether a non-official site plan is sufficient for our building application.

as a question. It can happen.

Here perhaps once again an explanation of when an official site plan is not required for a building application:
§ 3 BauPrüfVO
(3) The site plan (paragraph 1) and the calculations according to paragraph 2 must be prepared by a cadastral office or by a publicly appointed surveyor and certified with public faith (official site plan), if it is requested or

[*]1.
the outer boundaries of the building plot are not established boundaries within the meaning of the Surveying and Cadastral Act of March 1, 2005 (GV. NRW. S. 174) in the respectively applicable version,
[*]2.
the boundaries of the building plot and the existing structures on the building plot and adjacent plots are measured in such a way that coordinates for the boundary points cannot be determined in a uniform system, or
[*]3.
there are encroachments on the boundary on the building plot or from adjacent plots,
[*]4.
there is a building encumbrance within the meaning of § 18 on the building plot or a building encumbrance concerning the building plot on the adjacent plots

This means that if one of the above points (= characteristic fact) applies to the property, an official site plan must be available. If no characteristic fact is fulfilled, a non-official site plan is sufficient.
For us, none of the points apply. Therefore, an official site plan is not necessary.
However, I will call the building authority tomorrow as a precaution and ask.

Thank you Mickykitty!

Those are really interesting hints instead of the half-knowledge that is sometimes distributed here with full enthusiasm.

Certainly not.

How can you be so sure?

Because none of the points would apply to us either and we have already wondered why some house providers claimed that they could arrange a surveyor for us cheaply.

The thread could become interesting for everyone who does not have the surveyor included as a service. It could be that four-figure amounts are often overpaid here out of ignorance...

Then all those who mistakenly have an official site plan prepared for their building application have apparently fallen for this misconception. It would be possible, although I consider it unlikely.

Then all those who have fälschlicherweise commissioned an official site plan for their building application have probably fallen for this misconception. It would be possible, although I consider it unlikely.

No, an official site plan is never wrong, but in cases where the factual requirements of § 3 paragraph 3 numbers 1 - 4 BauPrüfVO are not met, it is simply not nötig.