how to adjust temperature reading on max31855

[c310]

hi! i installed old-style termocoulpe board that has max31855 chip, and readings are 4 degrees below

i reasearched M308 documentation, but was not able to figure out how to adjust readings.

please advise... and thank you in advance!

current config is

M308 S1 P"spi.cs1" Y"thermocouple-max31855" 
M950 H1 C"e0_heat" T1