I noticed that the temerature range in the freezer is 0Fto 25F. it seems like there is too much hystersis
I noticed the screw on the bottom that says colder and a screw on the side. Is the side the one to adjust the hystersis?
Do you think this is the problem?
With a temperature fluctuation of 25 degrees, the most likely issue would be that the unit is sticking in a defrost cycle or the operating thermostat being faulty. If you notice the unit being off for an extended period of time try to turn the defrost timer and see if it kicks ok. If not then the thermostat would be the issue.