Calculated temperature *will* differ from camera because camera and LibRaw uses different color profile (because color profile is used for xy-calculation)
The only way to check results is to compare to Adobe software (Lightroom or Camera Raw) with same color profiles (so, for example, DNG file with built-in camera matrices: ACR/Lr uses embedded color datain DNG case and LibRaw may be forced to do the same)
Calculated temperature *will* differ from camera because camera and LibRaw uses different color profile (because color profile is used for xy-calculation)
The only way to check results is to compare to Adobe software (Lightroom or Camera Raw) with same color profiles (so, for example, DNG file with built-in camera matrices: ACR/Lr uses embedded color datain DNG case and LibRaw may be forced to do the same)