Mike, I just went back and reread the Mosti instructions again. I had forgotten that Mosti adds the k-meta at the stabilizing/clearing phase (what they call phase two), but add the sorbate just prior to bottling (what they call phase three). In the video, George says to always add k-meta at the same time as adding the sorbate, otherwise you can end up with a rotten egg smell. That's why he reserves that 1/4 tsp of k-meta -- to add in conjunction with the sorbate at the bottling phase.
Kixx1185, I followed George's instructions in the videos when making my first kit -- a Mosti Vinifera Noble Pinot Noir. I added the k-meta that came with the kit at phase two as indicated in the instructions. Then, I also added the 1/4 tsp of k-meta with the sorbate just prior to bottling as suggested in George's video. I think I ended up with too much sulfite in my wine. I've had to decant that wine for at least an hour before drinking.