I don't think this is right. When I was doing aikido 'shomen' was simply 'the front'. I am pretty sure that's what it means almost universally whether talking about the position of the hips or whatever. Sometimes it means 'to the front' and sometimes it means 'from the front' but I don't think a height is ever explicitly implied when using the term. In aikido, with the use of the overhead strike that is so commonly used for an opening attack in drills, the hand of course strikes down toward the head instead of the body because the head is closer!