C120 - Fishfinder Setup missing from menu

I have a C120 and my fishfinder's temperature is reading a few degrees high. After consulting the manual, I see that can be adjusted via Menu -> Fishfinder Setup. However, when I select my Menu, there is no option for Fishfinder Setup. Am I missing something? I have a Fishfinder sensor installed, and it's passing depth and temperature to my C120. However, I see no option to adjust or calibrate it.

Thanks in advance for your help