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[herptrader]

You can never rely overly much on the markings on a thermostat. At best they will respond accurately to the temperature and the location of the probe. A thermometer, placed where you want to know the temperature is the only way to go. Better still, use a min/max thermeter and measure the range at the hot spot and cool end.

A thermeter gun is a really good way to check this out and they are a lot more affordable these days.

I don't think a little bit of temperature fluctuation is necessarily a bad thing as long as there is a good temperature gradient.

If you are trying to achive a stable temperature you may wish to consider using a dimmer, in addition to a thermostat, on your heat source (in this case a ceramic) and set the dimmer so it is on most of the time to achieve the desire temperature.