So I understand it correctly (if not, please explain): You want to build a house, but you don't really know yet what the house should look like. You go to the architect and have him make a design and also a cost estimate. Then you decide against the architect because his cost estimate does not meet your expectations. So you say to the architect: Sorry, but too expensive........, by the way, I’m not paying you either, I don’t see why I should! But I quite like your idea for the house, so give it here, I’m going to take it to the prefabricated house manufacturer because he will also give me a fixed price :-)
Or do you already have a floor plan, elevations on the basis of which a calculation can be made?
Have I roughly summarized this correctly on the whole?