Single-family house 159 sqm - Straight plot - Correctly calculated?

Dear Sir or Madam,

we are currently facing a difficult decision to acquire a plot of land 25 km from Stuttgart that actually does not quite fit within our budget.
In the past months, we have already "planned" our dream house without a basement with a well-known architect and created the following cost breakdown:




Some items may not be allocated correctly, but overall we would like to know whether the final amount is feasible or if we are completely off.
Attached are the first drawings!

Additional data:
- 450 sqm plot
- 159 sqm living area including utility room
- 18* gable roof 1.5 stories without basement

I have just built myself in a cheaper area. Sorry, but the cost breakdown, if these are not net prices (excluding VAT), will not add up. Better calculate an additional 15% on the house. Many small items are also missing in the cost breakdown (construction electricity, insurance, etc.) that cost money. I also find this negligent on the part of the architect.

https://www.hausbau-forum.de/threads/warum-ein-hausbau-fast-immer-teurer-kommt-als-kalkuliert.16237/

Geologist 3k I find a bit much. Our soil survey cost 750 €.

Otherwise many ancillary building costs are missing such as:
- Insurance
- Construction road
- Construction electricity, construction water, etc.
- Building application fee
....

I consider it too tightly calculated, unless you contribute a lot of own work.

I would always recommend accounting for at least 10% for additional costs. I don't know of a construction site without additional costs.

hm these are unfortunately not very pleasant news!
A 10% increase would be almost a total of 700k€ and that is not in proportion.

We had hoped a bit to have calculated too much in one or the other position and thereby save something in another position. Personally, I find the architect quite a lot as well but I thought that was normal and there are tariffs for that.