Thats what i thought but is that the real reason ?
The Top Sash window was Notorious for being difficult to open from inside, especially if they had not been opened all winter when the wood expanded, also paint causing it to Jam, they fitted the handles on the top window on the out-side, you would open the bottom window lean out and grab the handles to assist in the opening of the top window.
They were not put there for the benefit of w/c although when I was on my ladders they were very handy on high ones, I susspect Dave the windows there fitted to, are the larger sash type, they were fitted to the normal size ones but you see them more on the bigger ones as they were fitted as standard on installation.