SPACE - area tag - how to include door/window niches

[ixikEEA68]

I have floor-to-ceiling window. Is there a way to get the SPACE object to include floor area of the opening in the wall (door/windowsill "floor area")? SPACE, by default, ignores the floor area under the walls completely.

Blue - what I get in default

Red - what I would like to achieve with the SPACE object 

 

Thanks, any help much appreciated.