Just for some basics, the Campden is only used to help stop or prevent any form of wild yeast and some bacteria from reproducing. Campden will not stop/slow any brewers yeast.
K sorbate or Potassium Sorbate however, is simply a preservative and this does not kill yeast, it just slows or stops yeast from reproducing, even though you have a halted brew, you can however add more yeast to a point that will over take the preservative and cause a re-fermentation.
Hope this helps, notice we've had a lot of confusion especially in regards to this recipe. When I created it I only used the campden for the purpose of wild yeast prevention.