How and when is payment made?

Then mechanical engineers are in the same field as civil engineers... who also always think they know about surveying :D Meanwhile, the graduate surveyors are the only ones who really have the overview!! ;)

A mechanical/construction engineer had manually calculated the static structural analysis for the sold semi-detached house and was hardly or not at all able to understand that our structural engineer did not consider this "support" a good idea.

Yes, hmm, what was the problem? If the customer thought he could contribute his own static calculations and save real money, then he is stupid. If he only did the calculations to understand and plausibility-check the invoice of the (himself paid!) structural engineer, then it's okay. You just talk about it briefly and that's it. I admit: I do not know the whole case, only the lines above...

Our structural engineer recommended a different – but by no means worse – foundation than required according to BB due to the encountered soil conditions and seismic zone II. Our construction manager executed this recommendation cost-neutrally and we still discussed the why and how the engineer interpreted the structural analysis differently

Maybe. Another perspective: the developer was not able to explain the topic understandably to his customer (who is the one who ultimately pays). It might have been one way or the other; I am the last person to deny that there are exhausting, stupid customers!!!

But as I said, you are right. Customers who understand something about the subject are nonsense because they resist. And I only let myself be convinced if they come with reasonable arguments. Because "we have always done it this way" is the answer of a fool.

I would not completely endorse your post now, but at least those last sentences in essence.

Even I as a customer (I pay a fortune! I am a layperson, my counterpart is an expert!) have the right to have things explained to me. I don’t want to hear "We always do it this way"; "You do ask questions!"; "No one has ever asked that before!"; "What is your profession anyway?". I would often like to hear: You can do it this way or that way, pros/cons, costs.

Good evening,

If the customer thought he could contribute his structural engineering and save real money, then he is stupid.

You say ...

Another point of view: the developer was not able to explain the issue clearly to his customer (who is the one paying in the end).

What else can I say except that the structural engineer recommended a different foundation due to a combination of "x" and "y"? Since I assumed both could meet on equal terms, I established a phone connection to the structural engineer during the conversation. It did not really change the fundamental discussion regarding deviations from the owed building contract ....

I wouldn’t fully endorse your post now, but I agree with the sense of these last sentences.

With all due respect - this statement from Payday is nonsense. A reputable provider will not come at you with statements like "we have always done it this way." He will patiently explain until the penny (hopefully) drops. On the other hand, I have recently replied a few times with "no one has ever asked me that before," but with the addition "I will answer this question at the next appointment." I already have many answers, but certainly not to all questions ;)

Rhenish regards

I know that the machine builders in my field always have issues to crack, and yet, when a craftsman sometimes tells me that this or that is better / not so great, then many years of experience are behind that. It is worth thinking about that. Even though I have stuck my "nose" everywhere and have adjusted almost everything, everything was actually good from the professionals. Only the brine drilling I had drilled a bit deeper, but only to increase efficiency. Aside from that, I also have the tender texts/specifications for all trades, and there are really worlds of difference compared to the specification "such and such size and white". The window builder also filled quite a few pages. If you only give the dimensions and hardly any information, comparable offers never come out in life (if at all).

What can I tell

Yeah, no idea :D. It's obvious that even the most communicative, open, and factually correct, extensively informative developer will eventually encounter a customer (Murphy!) who doesn't understand any of it and is resistant to advice. (I used to be a DJ, I know this kind of thing ... :rolleyes:).

["at the next appointment I will answer this question for you"]

Honestly, with "our" developer I have exactly that impression (this is meant positively, a compliment).

A reputable provider

The layperson only knows afterward whether they have found one. And skeptical people expect the worst (the common saying also knows that when building, basically everything always goes wrong, you always pay more [than previously planned; than appropriate], ...)

It’s a bit like buying a (used) car. There is a huge power/information gap between the parties. Some bear this with resignation, others try to close the gap. The seller, if they cannot choose their customers, must be able to deal with this.