I had one of the sensors inside, and I was able to put it into setup mode and slowly recalibrate it. The highest value I could get it to take was 71.9 (and the inside temp where it was located was around 74).
However, once it sat on the desk for a while, and the setup timed out and went back into normal operating mode, the temperature reset to -24.5 F the first time the sensor detected motion. I have the sensor set to do a query on the device when it detects motion, as that seems to be the only way I could actually get any readings from the sensor other than motion sensing. The other two sensors are outside, and they require a bit of work to get to, so I'm testing with just one of the sensors for now. But the temperature of all three devices reads a steady -24.5 F.