The VE100 is also an off and on T-stat it will turn on until the spike raises the probe temp to the one degree over the set point. Then it will shut down until the probe temp drop below the set point. The average of the highs and lows should be the set point. Then you add in ambient room temps. These can cause the probe to heat slowly or quickly and alter the average. This begs the question what is the ambient room temp? If I were to guess I would figure it is low to mid 70s? If so raising the room temp to 80 may solve the issue of a cold probe.