There's a lot of issues I've been having using this, since I decided use this for my first patch. Sadly there's still a lot of cases I need replicate so I can make a useful report out of this.
Basically, I started get issues where when I added strings or added new values in life from map they appear all fine, even after saving, but it just refuses to work in-game. Nothing gets changed. This actually took me a full hour of annoyance (since I had no idea what went wrong) before I realised its this tool causing the issues, since it worked right away on vanilla repacker.
When I get the time I try replicate some of the issues and report it here.
Basically what I am understanding the tool see the changes, but doesn't apply them correctly, only visually in the editor. This is not always the case though, since I've also used it successfully.