diff --git a/src/pyob/xml_mixin.py b/src/pyob/xml_mixin.py
index c472551..ad7e26c 100644
--- a/src/pyob/xml_mixin.py
+++ b/src/pyob/xml_mixin.py
@@ -274,9 +274,14 @@ def _attempt_line_by_line_match(
                     match = False
                     break
             if match:
+                # Apply indentation fix to replacement lines
+                fixed_replace = self._fix_replace_indentation(
+                    "\n".join(code_lines[i : i + len(search_lines_stripped)]),
+                    "\n".join(replace_lines),
+                )
                 new_code_lines = (
                     code_lines[:i]
-                    + replace_lines
+                    + fixed_replace.splitlines()
                     + code_lines[i + len(search_lines_stripped) :]
                 )
                 new_code = "\n".join(new_code_lines)