...why not make it a proper dance-off? Rather than merely repeating the choreographed dances from the main show, why not play, say, some waltz music and have both couples waltzing around the floor at the same time. Given that the contestants are supposed to have learned some technique, it would be much more interesting as a decider, and would actually give the judges something to talk about.
There you go, that's my solution to save the SCD format.
There you go, that's my solution to save the SCD format.