Ceiling outlets for controlled residential ventilation, is that correct?

The planning of the air volumes does not seem to come from a layperson after all?! Relying blindly on "planners" for technical design and implementation is comfortable, but (unfortunately) rarely the ideal way as can be seen here. It can always be done better, but it is important to prevent gross errors.

Sorry, I would not let any layperson plan this, but follow the suggestions of the architect, heating engineer, and planner.

Many heating engineers or architects cannot do it; usually, building engineers do it. (I think that’s what they are called )

This plan was created by a large controlled residential ventilation supplier (only certain employees do it there, whether they are planners?), whether it is really correct now, I cannot say at the moment, that’s why I posted it, maybe a planner happens to be here .

This plan was designed by a major controlled residential ventilation supplier (only certain employees do it there, whether they are planners?)

That's how it should be. It may be that one or another here happens to make the right suggestion, but I would not place any value on it. My opinion!

It may be that one or the other here makes the right suggestion purely by chance,

Planning the ventilation is not rocket science. I had already pointed out that I am not a professional so that the OP can appropriately assess my suggestions.

As long as no one is personally attacked, it is not wrong.

I had informed them that it is often heard that controlled residential ventilation systems are loud. I was then told that planning and calculation are therefore very important. The calculation was done according to DIN, the supplier is said to have a good reputation, and actually, he could not afford to have calculations done incorrectly.

An acquaintance told me that he always goes by *P x Daumen*.

Of course, errors can always occur.

Therefore, stop the planning here or elsewhere and you can only benefit. It's like with the floor plans, there is often good input there as well, not just by chance.