Window reveal before window installation... smooth coat?

Good day dear community,
we are now about to install the windows… as far as I know, the window reveal must always be filled before installation.
This has been done everywhere, but as a layperson I am not sure if this is OK..? My site manager tends to say "yes" to everything and therefore does not really have the expertise (a request for a replacement has been made).

From the picture it can be seen that this was done only with cement mortar.
The structure of the exterior wall is: 1 cm plaster (interior), 17.5 cm Poroton, 16.0 cm insulation, 1.5 cm plaster (exterior)

From acquaintances who recently built, I heard that a smoothing coat still needs to be applied. Is there any truth to this, or would it also work like this (see picture) to ensure airtightness?

Glattstrich is done on the joints of exposed or facing masonry. Windows are installed in the rough opening, which has not yet been plastered. Why do you want to smooth something there?

A smoothing stroke is applied to the joints of exposed or facing masonry. Windows are installed in the shell opening, which is not yet plastered. Why do you want to smooth something there?

Regarding the sealing tape and the adhesive foil.

That's how I know it as well and that's how the window installer wanted it, and it was accordingly executed all around by the shell builder - but it was also part of the company's standard scope of services.

Regarding the sealing tape and the adhesive film.

And you fear that to them the joint interlocking is too bumpy? Where exactly is the installation plane supposed to be?

That's how I know it too, and that's how the window manufacturer wanted it, and it was accordingly executed all around by the shell builder - but this was also part of the company's standard scope of services

And that is now the question I am asking myself among other things.
The main question, however, remains whether it is necessary..?