I have a Craftsman electric miter saw. One of the click-stops is at 31.6 degrees. What is this angle measurement used for?

I was using it a couple days ago and it was cutting perfectly. Now i go out yesterday and somehow its cutting a few degrees off of what it should be. Can it be fixed?

Hi i just got a Hitachi slide compound miter saw model # C12RSH and cant find the serial number on it anyone know where it is?