On my(and many others bosch iat) the best matching curve from cltfactors.csv is 2063_256. But on -10C he shows -7C, and on +80C he shows 75C. On 20C readings are correct.
So i made new curve base on bosch information.
http://www.bosch-motorsport.de/pdf/sensors/temperature/NTC_M12.pdf
and
This is that curve for clt
http://www.vems.hu/files/DamirMuha/bosch%20clt/cltfactor_2063_256.clt.txt (you must rename to cltfactor_2063_256.clt)