I'm not sure the wording of the procedure is correct. That example of moving from flaps 5 to flaps 1. You are selecting flaps up and get an asymmetry. There's little point in continuing retracting the flaps. Logic dictates that in the event of an asymmetry you should select back towards the last position the flaps passed through before the asymmetry became apparent.
In any case, the flap asymmetry system is designed to lock out the flaps and prevent further movement. In either direction.