Does your GPS module put out more decimal places in the LAT/LON fields?

Since the edge of the square runs through the middle of the house, whether you're at the front window or rear window inside, you're always near the edge.
I imagine that if you were standing in the middle of your back yard, the reading would be more consistent.

One or two more decimals may improve the resolution considerably.
With only two decimals, a difference of .01 is a whole square.
Code:
    LAT           LON       Maidenhead   
Deg Min.Min   Deg Min.Min   1234567890
------------  ------------  ----------
 53° 25.83'    -0° 49.77'   IO93ok03kh  Back Yard
 53° 25.82'    -0° 49.77'   IO93ok03kg  Front Yard
It depends on whether your GPS gives enough data or not.
When recording NMEA sentences from my Android, it gives 6 decimals.