diff --git a/scripts/sipify.py b/scripts/sipify.py
index 6f9f943c1a5..02da8618193 100755
--- a/scripts/sipify.py
+++ b/scripts/sipify.py
@@ -1868,11 +1868,11 @@ while line_idx < line_count:
 
             if is_override_or_make_private == PREPEND_CODE_VIRTUAL and not re.match(r'^(\s*)virtual\b(.*)$',
                                                                                     rolling_line):
-                idx = len(output) - line_idx + rolling_line_idx + 2
+                idx = rolling_line_idx - line_idx + 1
                 output[idx] = fix_annotations(re.sub(r'^(\s*?)\b(.*)$', r'\1 virtual \2\n', rolling_line))
             elif is_override_or_make_private == PREPEND_CODE_MAKE_PRIVATE:
                 dbg_info("prepending private access")
-                idx = len(output) - line_idx + rolling_line_idx + 2
+                idx = rolling_line_idx - line_idx + 1
                 private_access = re.sub(r'(protected|public)', 'private', last_access_section_line)
                 output.insert(idx, private_access + "\n")
                 output[idx + 1] = fix_annotations(rolling_line) + "\n"