How many times have you been told on the Feather Step Foxtrot to step outside the lady on step 2 and 3. For a start the technique book doesn't say that. What it does say is LF foot forward preparing to step ouside the lady with the left side leading. That is not stepping outside lady because in your Stance with your partner the LF is already on the outside. Why would anybody step outside with a foot that is already naturally outside. It might be worth taking a look at the ladies steps and see what it says about them.It might have been better if the book had said the lady allows the man to be on the outside on step three. The man takes the straight line. The lady makes space so that he can. Also that CBMP on the third step is more severe than most of us try to be.

Hi Serendipity
I think what it means is that the next step (i.e. with the right foot) is outside, so you're preparing for it with the previous step.
If the technique book were being updated, it possibly would say it differently