Adding X, Y coordinate data to a layer in ArcGIS 10

My point pattern data had been previously geocoded but did not include coordinate data, so I added it:

Opened attribute table. Added new field “X” (Type: Double). Right clicked new field, selected “Calculate Geometry” and selected "Property: X Coordinate of Point", "Coordinate System of data source (in this case, GCS: North American 1983), and Units "Decimal Degrees". Repeated the process for "Y" coordinate.

For some reason, the new fields initially populated with "1"'s. I closed the attribute table, removed the layer, re-added the layer, opened the attribute table, and the coordinates magically appeared. This only happened once; further additions of coordinate data to different layers populated correctly.

My unmatched records populated the coordinates with "1".