What temperature should Frigidaire frost free commercial freezer FFU14FC4AW0

I just recently purchased a used Frigidaire Frost Free Commercial Freezer. As indicated above it is a model FFU14FC4AW0 and was manufactured in 04/2002 so it does have some years on it. One thing I need to know is what the temperature inside the freezer should be. I am sure there is a temperature range that is ideal between two degrees of temperature. Our normal refrigerator/freezer may have us a bit spoiled because with it on just one click below 1/2 the freezer maintains -10 F year round and freezez ice in trays very quickly. This Frigidaire Commercial Freezer has been operating between 9 F and 18 F and I need to know if 18 F is considered to be operating well ? The fact that it is indicated as a Commercial unit matters ? Does that mean it maintains a lower temp and built more robust than a standard home unit ? Or just that parts will cost more to purchase ? Also this freezer seems to be running a lot of the time. It is nearly 3/4 full of food items and bags of ice that are distributed throughout the freezer fairly evenly.