Working on a thermal expansion problem.

I have a part that is initially 220C.  So for the zero-strain reference, I input 220C.

Now the part cools down to 23C.  So I select the entire part and apply a temperature load to it.  Which of these scenarios is correct:

1) I input a temperature load of 23C.  SolidWorks calculates the part cooling from 220C to 23C.

2) I input a temperature load of -197C.  SolidWorks calculates the part cooling from 220C to (220C - 197C = 23C)

I have been taught that the 2nd way is how to do it.  Is it still correct, never correct, or recently changed?

Thanks!