diff --git a/Marlin/ubl_G29.cpp b/Marlin/ubl_G29.cpp
index 8c2f7d47c..f603ec8ee 100644
--- a/Marlin/ubl_G29.cpp
+++ b/Marlin/ubl_G29.cpp
@@ -1664,7 +1664,7 @@
             }
           #endif
 
-          z_values[i][j] += z_tmp - lsf_results.D;
+          z_values[i][j] = z_tmp - lsf_results.D;
         }
       }