here’s a test. Hold the thermistor to heat it up, does the temperature your application reports go up? Put it in some warm water, same deal does the temp go up? Put it in the freezer, does the temp go down?
As you can see from the driver, the thermistor is a very simple device; it simply changes resistance as temperature changes. The Fez is simply reading the voltage through the thermistor that is connected to the ADC.
That scales the values from the ADC. The ADC resolution means you can read from 0 to 1023, or 1024 steps. That means that each step is (56 - -22)/1023 or 78/1023, or 0.076246 degrees per step. 10 degrees means the ADC is reading between 420 and 432 (depending on how the rounding is being handled, it could be +/-6 I guess).
You could try commenting out the scaling statement and find what the return values are to confirm that.
You could adjust the scaling to return the right value for you. The challenge is that to accurately do this adjustment you need to calculate the value at at least two different points. Really you need to do a LOT of sampling, at multiple known temperatures, so you can get an accurate model of the thermistor’s response. But doing a couple of tests and comparing the returned value and a quick calculation can tell you how to set the scaling.