The accuracy will be good if you are not using the internal oscillator. You need a crystal or external "can" oscillator for better than 2-3%. If you need really good accuracy, you can (temporarily) shorten the time interval to one day (or so) and compare it to a clock. For example: if you are 1.3% "fast" then increase the value after the PAUSE by 1.3% (60780). That should get you close enough.