Exporting a coverage to a shapefile, using ArcCatalog or ArcToolbox, may truncate the values for particular fields.
The algorithms ArcCatalog and ArcToolbox use to export coverages to shapefiles assign precision and scale to the output fields, which may truncate values. If the original coverage field is a float with no set precision and scale, ArcCatalog and ArcToolbox will set a precision and scale for this field in the exported shapefile. Sometimes the set scale will not be large enough to capture all the data from the decimal.
Verify the file format is specified as shapefile in the Save as Type dropdown list.