The other thing to consider is the quality of the space. The rooms created would be just under 3m x 3m (approx 9ft x 9ft) which would be very tight for a double bedroom. So this means this space could be used for a small bedroom or perhaps bathroom or dressing room depending on how the internal layout turns out.
One of the biggest mistakes when choosing the right floor plan is that you forget to picture your own family cooking in the kitchen or you don't take into consideration how your bad back may not like going up 3 flights of stairs throughout the day. Assess your lifestyle before choosing a floor plan. Do you like a single story or multistory home? Do you prefer an open floor plan or are individual rooms with partitions better? Determine what you have become accustomed to in a comfortable home.