Should a hanging plot be filled for a ground slab?

Hello dear all, I had already raised the topic of basements/partial basements because of a 19% sloped plot for discussion. Now a house provider is telling us today that (also due to the high cost of building materials) it would be cheaper to fill in the slope and then build the house with a slab on grade... that doesn’t quite make sense to me, since the fill material must have support somewhere, for example with a concrete wall. No, says the seller, they simply let the compacted fill gradually taper off to then plant the resulting new artificial slope, for example. What does the expert community of this forum say about this?

Filling is moderately expensive, but all the reinforcements rip you off. In the end, you have a modest cost-benefit ratio. With the picture and 19%, I would definitely not force the property onto a slab foundation. It doesn't really save you money and you lose the space from the basement.

I agree completely. It also depends on the size of the plot. If the construction company suggests to "phase out," then they should calculate how long this phase-out period would be and what would remain of your plot afterwards.

EDIT:
And, I really can’t clearly see your approach anyway. I would just have it calculated now before you start the second thread here about the theoretical determination of "what might be cheaper" ;).

What does the expert community of this forum say about it?

A beautiful residential tower would be created there, which would overwhelm every viewer from below. Just the suggestion alone would lead me to look for another building partner.

A nice residential tower would be created there, which would overwhelm every viewer from below. Just the tip alone would lead me to look for another building partner.

I was already skeptical on my own because the house seller would also sell a larger house with that variant…..

I don't quite understand that,

I couldn't have said it better myself, and I fully agree with

then he should calculate how long this runoff would be and what remains of the property for you.

Besides, a relatively flat slope (which I don't even see here) does not "hold" by itself, and is at least pure nonsense if the proposer has not first read from the soil report that particularly favorable conditions are explicitly given for it.