How come moving it up gives you colder temps.
As you know. There is a major UP-DRAFT over Capitol Hill (most all "Capitol Hills" due to all the hot air that is given off in the houses of government. (NOTE: this is a joke).
Seriously. "Hot air rises" thus in the fridge the top is warmer than the bottom. Moving the thermisistor UP moves it into an area that is naturally Warmer,, and since it is the sensor for the thermostat, when you cool that spot to the target temp. The rest is colder. Moving it DOWN moves it to a cooler level, so now the rest is warmed a bit because the sensor cools sooner.