The reason I bring up a candy thermometer is the accuracy required to successfully blend and make either sugar based, butterscotch or chocolate confections is quite temperature dependent between scorching or success and the candy thermometer is a precise measuring instrument required. The candy thermometer is accurate to 3 Fahrenheit and only professional lab equipment would be more accurate. Most consumer appliances the accuracy of the rheostat and sensors drift at low temperatures below the 325 - 425 Fahrenheit average cooking temperature range. With professional restaurant equipment the rheostat dials which are selected are quite accurate. Every consumer appliance is built to operate within a narrow common usage range and the rheostat components are imprecise below or above. The temperature drift of the unit you are using may be at cause for low conversion of THCa to active THC. Please do not use soy derived lecithin, it is incompatible.