I'm trying to calibrate one of my ds18b20 probes which is reading wrong (when compared to a lab thermometer) so I added a negative linear offset to the probe element.

When using this probe as an input for a heater output element, although it shows the calibrated value as the input, it still seems to be using the initial value for the control

Example: initial value is 15, after calibration (linear offset of -5) it reads 10.

I then set an output target of anywhere between 10-15 and there's no output, go above 15 and it gives an output.

Not sure if I'm missing something obvious here but just can't seem to figure it out.