Try this.
Take a character, set it to be a different race. Likely, the face will not change. If going from humanoid to khajiit, it will look especially horrible.
Now, set it to another, different race. Suddenly, the face conforms to the race! (you can get hilarious cat-painted faces if your starting race was khajiit).
Interestingly, sometimes it seems like this conforming face is the 'default' face for the race. Othertimes, it seems like it uses the racemenu parameters but puts it through the proper racial filter.
Switching back to your starting race restores the face to its original settings.
This also works if you've done the six-change command. After 2 race-swaps, the face will be female until switching back to the start.
BUT
About 25% of the time this not the case - changed characters will lose their head, or will lose their original race settings. (For example, old ladies usually end up looking very young after this process - but not always!)
Has anyone else been screwing around with these commands? A shape-shifting item would be really fun in this game.