nice coffee! Thanks.
The other useful part of the semi-circle manoeuvre is that it indicates to we ladies which foot to step back on. By doing it, it slightly opens out the position between both dancers (assuming you're keeping some tension, that is!).
Try doing it in the conventional direction (anti-clockwise for you chaps) whilst the lady steps back on her right foot (say she was going into a return, for example), and see how awkward it feels for her. (Of course, this only applies to a class environment!)
In free dance I'd expect to start back on my left by default, anyway.