Kenmore 14.8 cft - temperature between 5 and -22 degrees (-15 and -30 C)

Big...this is likely normal. I'm not sure where you're measuring that temp from. If it is the fan outlet, this is possible. The fact that the unit is staying below 5 degrees means that it is within spec. You do have a warranty. Ask Sears to come on in and check it out.

Your 'duty cycle'...that amount of time that the compressor is on should be about 20% of a unit of time...say 25 minutes out of 2 hours. Is that about right? If so, enjoy your ice cream.

We had somebody there from Sears who claimed he could not check anything because the temperature was set too low. He turned the thermostat to "4" (that was in the morning) and told us he was ordering some replacement parts. When I got home in the evening, there were parts in the upper part of the freezer that were defrosted. That freezer is a piece of junk and I will very likely call my credit card company to get it returned as Sears would only take it back for a "restocking fee"...
Tom