Calculating according to DIN is not a rip-off
eyes wide open
And what do you get from the DIN as a builder and buyer? Exactly nothing.
As a seller, of course I can count my 70 sqm
terrace as 50% of the living space according to DIN. But come on, please. You don't have to defend that.
Besides, I already wrote... like in apartment construction. Only that I don't expect that in house construction and neither does the OP, otherwise he would have written 115 sqm of living space. Unless he also thinks in DIN :p