Difference in area between projections

gistfile1.txt

CREATE DATABASE ky;
CREATE EXTENSION postgis;

shp2pgsql -s 4326 senate_4326.shp | psql -h localhost -U john -d ky -p 5432

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 102680, 'ESRI', 102680, '+proj=lcc +lat_1=36.73333333333333 +lat_2=37.93333333333333 +lat_0=36.33333333333334 +lon_0=-85.75 +x_0=500000.0000000002 +y_0=500000.0000000002 +datum=NAD83 +units=us-ft +no_defs ', 'PROJCS["NAD_1983_StatePlane_Kentucky_South_FIPS_1602_Feet",GEOGCS["GCS_North_American_1983",DATUM["North_American_Datum_1983",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic_2SP"],PARAMETER["False_Easting",1640416.666666667],PARAMETER["False_Northing",1640416.666666667],PARAMETER["Central_Meridian",-85.75],PARAMETER["Standard_Parallel_1",36.73333333333333],PARAMETER["Standard_Parallel_2",37.93333333333333],PARAMETER["Latitude_Of_Origin",36.33333333333334],UNIT["Foot_US",0.30480060960121924],AUTHORITY["EPSG","102680"]]');

SELECT AVG((stateplane_area-wgs84_area)/stateplane_area) AS diff FROM (
  select st_area(geom::geography) AS wgs84_area, ST_Area(ST_transform(geom, 102680))*0.09290304 as stateplane_area from senate_4326
) q 

-> 0.00076% average difference in area measure in square meters