Precision of code is trade off with cover area and length of code. Some code choose flexible code schema like decimal value. For example, NAC can express about 1.6 by 1.6 meters by 10 digits, but can be 0.05 by 0.05 meter with 12 digits. N-Code, GeoPo are the same.
Some code have fixed precision and fixed format. LocaPoint express 0.4 by 0.8 meters with 12 letters, LP-Address expresses 1.1 by 1.1 meters with 12 letters, and MapCode express 30 by 30 meter with 10 numbers.