diff --git a/PARAM/HMS/DC/GEOM/hdc_geom.param b/PARAM/HMS/DC/GEOM/hdc_geom.param
index 6a42cfe983789ec6ecd105358c25e2cdeb3a4143..348439e825b57a399d457224a0d657f183117e8e 100644
--- a/PARAM/HMS/DC/GEOM/hdc_geom.param
+++ b/PARAM/HMS/DC/GEOM/hdc_geom.param
@@ -45,8 +45,8 @@ hdc_readoutTB = -1, 1, -1, 1, 1, -1
 
 ;HMS DC Surevy Source: Jefferson Lab Alignment Group Data Transmittal
 ;dated 30 Nov. 2017, Checked #: C1832
-hdc_xcenter = -2.227,-2.232; ; obtained from 11/29/17 Survey
-hdc_ycenter = -0.01, 0.009; 
+hdc_xcenter = -2.227-0.04,-2.232-0.04; ; obtained from 11/29/17 Survey
+hdc_ycenter = -0.01-0.26, 0.009-0.26; 
 
 ;HMS DC Surevy Source: Jefferson Lab Alignment Group Data Transmittal
 ;dated 30 Nov. 2017, Checked #: C1832