Correct. What I am saying is that you don't need to move your save from the previous version over. That save in #20 starts you as having completed everything up to that point that is new content in the new version. It's a 100% save from the previous. (to keep from having issues, just like this).
Since there is no save in the slot that your old save is numbered for - RPGM will not show that save in its list within the game. If you want that to happen, then you can try to get this to work by following these steps:
- Exit the game
- Make sure your old save is not in the save folder
- Start a new game (or start from save #20)
- Save to the game in the same slot that your old save is numbered for
- Exit the game
- Copy your old save to the save folder, overwriting that new save
- Start the game using save slot you made (should access your old save data now)
That may or may not work. Let us know what you decide to do and if it works for you.