3rd out on appeal

[Steve M]

Wait a minute, part of your play was not an appeal.
"OBR has some odd wrinkles on missed bases that are forces. For example: 2 out, Abel on 3B, Baker on 1B running on the pitch. Charles grounds to F6, whose throw to F4 is too late to get Baker at 2B. Abel scores. However, Charles slides by the base without touching it and is tagged out trying to return. Ruling: Charles is out, but Abel's run counts. The defense cannot then appeal Baker's miss of 2B. So if you were talking to a bunch of hardball umpires, I'm not surprised there was disagreement."

Charles' sliding by the base and being tagged while trying to return to the base is identical in baseball & softball - that's a timing play and Abel's run will count in any softball sanctioning body I know about, along with any baseball sanctioning body I know about. That is not a missed base appeal.
In your play, your missed base appeal is a 4th out appeal. Some sanctioning bodies will accept this specific appeal while others will not - since Charles' run is not the run you want to take off the board.