I have a Johnson digital controller. I was just a bit confused by your temperatures, but Florida explains a lot!
Mine is primarily used to keep my fridge at a serving temp, since my brew room stays at 68 to 70 this time of year. Come summer I'll add a second fridge to better control fermentation temps.
A question, for days when the ambient temp is below 68, do you have some sort of heating element in your fridge?
Thanks,
Dan