Fleeting Frames: I couldn't quite understand your comment and I also couldn't find a description in the link you provided. I wonder if you could explain a bit more.
You say that 1 and 2 will have a greater value than 3. Did you mean the opposite? My understanding is that the middle room would have a higher value because it shares walls with both 1 and 2. Rooms 1 and 2 only share one wall each and so should have less value. Possibly I'm confused about something ;-)
(I have not done this experiment, at least in the manner of quantifying/qualifying things so precisely, but....)
I think the idea is that the shared wall counts as penalty. The middle room gains from its higher values, but less so from the higher values that are deemed 'shared' with the neighbouring rooms. The outer rooms lose (gainable) value in their neighbourliness with the central room, but are not suppressed for the other five tiles of the eight
1, so are better rooms because of this.
Or that's how I read it. I stand to be corrected.
1 One floor and seven walls (three/six of which are shared), the door all possible obscuring improvements to the floor that is the ninth tile, if it still works the way I'm used to. (I smooth and clear loose rocks away from doorways before even thinking of placing doors, but this scenariondoes not do that, in order to force the standardised test scenario.