Single-family house - is a discount over 10% realistic?

Whether the price is realistically sufficient doesn't matter to me, because the approach of moon prices and, if necessary, hefty discounts is unprofessional. In the end, they build only exactly what is necessary; if they have a quiet customer who trusts them, then they just botch it. Our counterpart had such a joker, master quality was promised, but only Afghan crews came who, poorly paid, barely managed to put up the house; then the heating didn't come at all, the so-called master simply closed the business, the customer had paid in advance and got nothing. Boom, it's an industry where besides honest craftsmanship there are endless fortune hunters. Now in the boom, they want to make money, then hit your money and run.