After Preliminary Sketches are complete, final sizing and structural considerations are changed to respect the limits of the clients budget. Room sizes change, doors change location and different roof angles might make second story windows larger or smaller. It is a Rubick's Cube. Here is one example of an open plan 1600+ sf house with a 2 Car Garage and 3 Bedrooms.  The garage was relocated (flipped) to allow more driveway parking for visitors and less sf.