Is it possible to reduce the size of the house after the financing is completed?

I have already taken that into account with the 2500€/sqm. If that’s not enough for you, just calculate with 2300€ or whatever you think is appropriate. It makes no difference.

Have you read my post? What you are trying to calculate there just can't be right. The few square meters of wall/floor typically cost significantly less than the commonly mentioned flat-rate costs, but the expensive items don't become less because of that.

Have you read my post? What you are trying to calculate there just can't be right. Those few square meters of wall/floor typically cost significantly less than the commonly mentioned flat rates, but that doesn't make the expensive items any cheaper.

Roof structure, roof, earthworks, etc.? The costs certainly don't decrease linearly, but I don't think we're talking about just a few euros.

The costs are all there anyway and only marginally smaller through extension/shortening. In other words: Not every square meter of the house has the same flat rate. The first square meters (which also include these [Sowieso-Posten]) are the most expensive. As already mentioned: In our case, the extension by one meter (to twelve meters length) would not have cost 10 K EUR. But if this provider calls for 60 K EUR less for one meter shortening, then go ahead - it just doesn't seem consistent to me.

…from the 7th meter onwards cancellation, the builder even gets something out of it. I would do it. :D

No, seriously. Never cost savings of this magnitude.

So we actually requested a reduction of 1m (with us to 9m length, basement, ground floor, upper floor, attic) from 2 providers as well. Without any other changes. With the prefabricated house, it would have made a 25k difference and with the solid construction 30k. For us, it was too little savings for a lot of quality loss. But the amount is of course not negligible.