Why does my air compressor not shut off right away when it reached the set pressure?

Our Air compressor is designed so that the unit must fill to the full desired PSI before shutting off to ensure you have enough air in the item you adding air too. For example, if you set your compressor to 33-PSI, the unit will run all the way to 33.49 PSI as we assume when you remove the valve, some air will escape.