diff --git a/python_scripts/run_simstadt_from_python/variable_window_ratio.py b/python_scripts/run_simstadt_from_python/variable_window_ratio.py
index a8044b01604d90a6fb2f012dd9242e6e2711235c..867548acc18b5950b8b8f7b005e4acf2f3ae1b4a 100644
--- a/python_scripts/run_simstadt_from_python/variable_window_ratio.py
+++ b/python_scripts/run_simstadt_from_python/variable_window_ratio.py
@@ -46,20 +46,20 @@ lib_node.text = str(custom_library_path)
 tree.write(physics_processor_params)
 ##########################################################
 
+with open(custom_library_path) as library_file:
+    content = library_file.read()
 
 for window_ratio in WINDOW_RATIOS:
 
     #################### Update lib with custom values ############################
-    with open(custom_library_path) as library_file:
-        content = library_file.read()
 
     new_content = re.sub(r"<name>[\w ]+</name>",
                     f"<name>Custom Physics Library with Window Ratio : {window_ratio}</name>",
-                    content,
-                    1)
+                    content, 1)
+    # FIXME: Use et.parse instead. Because groundSurfaces shouldn't have any WindowRatio
     new_content = re.sub(r"<windowRatio>[\d\.]+</windowRatio>",
                      f"<windowRatio>{window_ratio}</windowRatio>",
-                     content)
+                     new_content)
 
     with open(custom_library_path, 'w') as library_file:
         library_file.write(new_content)