What is the power percentage going to the flexwatt from the Herpstat?

I use the Herpstat 4. This is what the screen looks like



It tells me the current temperature, the set temperature and how much power is being sent to the heat tape. (I believe on some Herpstat models you have to cycle through the display screens to see the percentage)

If the Herpstat is running the heat source at 100% constantly then you need more heat tape. If the thermostat isn't running at full power than I would try adjusting the probe placement.