I have been getting horrific shrinkage on my candles lately with 4627 and I haven't changed a thing - following my same recipe, heating glass to 190, heating wax to 185, cooling in Styrofoam cooling boxes. The changes in temperature (cold to cool, cool to warm, etc) I think have been helping create huge "wet spots" on the sides of the glass - really big horrible ones that I have to reheat in order to sell. So frustrating, especially when I have to transport the candles to shows and back again.