HOAI or why architects have no interest.....

So: our architect charges according to HOAI, BUT he takes a smaller construction sum and told me that he has to charge based on this sum, otherwise it would be unprofitable for him. Our house is estimated to be ready for occupancy at 560k, but the bill is based on 300k.

That doesn't really make sense... "It's not worth it for me to charge you 50k€, so I'll only charge you 30k€..."

I'm just not sure about that: As far as I know, an architect can still charge retrospectively according to HOAI - regardless of whether a flat rate was agreed. Whether he does so is, of course, another question..... (where there is no plaintiff, there is no judge).

No, HOAI applies "unless otherwise agreed".
Only with public authorities is HOAI legally binding.

Even with differing agreements, the minimum and maximum rates cannot be circumvented.

There are different opinions here regarding the compulsory application of the HOAI, and even lawyers do not all share the same view. If flat fees were inadmissible or immoral and therefore invalid - meaning even "good faith" would not apply - I would consider it fraud if an architect offered them (with the intention of claiming more later). On the other hand, I do see - the example of notaries was mentioned, after all - a valid reason for a fee schedule for professions with particular liability risks: these risks are equally "severe," even if the professional works "for half the price."

However, such a fee schedule is really unrealistic incense waving if the young architect has the choice to either earn his bread qualifiedly - but at the cost of market-appropriate conditions - or "alternatively" drive a taxi at night or keep the waiter job from his student days, because no client accepts the fee schedule price (and is rather satisfied with the general contractor’s lackey).

The entirety of the statements reinforces my opinion that the billing bases regulated by HOAI (e.g., depending on construction costs) represent a one-sidedly advantageous methodology today. An architect should receive a correct fee (taking into account their risks). However, construction costs as a basis are unsuitable: The efforts/services of the architect should serve as the basis. : Share your opinion that HOAI regulations (minimum and maximum rates) cannot be circumvented.

What nonsense, one person claims rubbish, another thinks it's true and suddenly "fake news."

If an architect offers a private client the planning for 10k€ then he is allowed to do so, even if the HOAI perhaps states 20k€ as a minimum rate. (Period!) The HOAI applies here if nothing was agreed upon. Suppose you go to the architect, say what you want, and he plans something for you without you having agreed on a fee, then he can charge according to the HOAI.

It is also incorrect to back this up with facts saying the HOAI is a one-sided advantage. No one just came up with the price tables while drunk.
The HOAI will be abolished soon anyway due to EU issues. In countries where this has already happened, you can see that prices for planning services briefly fall - then the offices go bankrupt and prices settle above the HOAI equivalent.

Minimum and maximum rates cannot be circumvented even with different agreements.

What does this concretely mean for a client who has agreed on a flat fee with the architect?