The reason I'm concerned is because it shows 100 percent power until it gets close to my desired temp then runs around 60-70 percent. Then it typically will cut all power to 0 percent for a few seconds when the probe goes over set temp then goes back to 60-70 percent . I just assumed the heat tape got hotter than the set temp when it is being powered at 100 percent to get the probe to read the desired temperature. In other words I view 100 percent as the same as plugging the flexwatt directly into the wall.