ACA-2013 v 0.6.3 was just released.
This version solves a major bug in the renumbering of the fltsim sections feature.
There was a report that while renumbering the last line of the aircraft.cfg file was read, but not written back to the new cfg file, resulting is a missing line.
So please check your cfg files for missing lines.
I also added a version backup, every time you use this fucntion a new backup file is created, so an old backup is not overwritten.
You can find the new version in the download page