When our routine doesn't fit the floor, we just keep doing it and turn the corner. We could probably put in some step that effectively turns the corner for us, but as social dancers before comp dancers, we just don't see why we can't turn the corner when it gets there, and never mind about making different routines for certain length floors.
It gets harder as the routine gets more complex - some step sequences are not easy to segue out of, in particular when you have spent a gazillion hours learning it! But you are still right, you should be able to do so...