That's very strange indeed. All the code in the car itself uses metric measurements for temperatures, and I have confirmed via the ADX files for 1990-1996 that the equation never changed from 1990, which was "Count x 0.75 - 40 = Deg C". In fact, if you test my original unaltered code in your car you can confirm this for yourself.

My code was originally designed as a proof-of-concept to allow someone to make the CCM happy while spoofing the coolant temp. If you set the coolant temp value in my code to CD (205 counts), the dash should display 236.75F (I forget if it rounds up or down). This is because 205 x 0.75 - 40 = 113.75C, which is 236.75F.