Hello all, just got a coolfire z50 kit, which has the zlide tank with the zenith coils. I primed the 1.2 coil which came with it and starting using it with 6mg 50/50 juice. I have used about a full tank of juice starting at 10w, but it starts to taste burnt at 11w with 1 hole open or 11.5 with 2 holes open. Surely the coil should be able to go to a higher wattage by now after using a full tank of juice? Any help would be much appreciated.