While searching around on this, I found an old article on Allan Wyatt's "Tips.net" newsletter for Word. This may or may not be helpful.

Stopping Styles from Changing with Multiple Users (Microsoft Word)

One of the suggestions was that you start with an original "base" style and have all your styles use that as the base. I see you do have a My_00_Body_base, but your subsequent My_01 styles show (in the Modify pane) as "Style based on (no style)." I have never personally seen that matter on documents shared between users, but the article suggests this might help.

Also, check that your daughter's "Normal.dot" doesn't have conflicting Styles or Style Names? I can't imagine this as an issue unless there were previous versions of these styles with the same names.

Charles knows far more than I do, and whether this suggestion is worthwhile, I'm not sure. I've found some decent tips in that column in the past, but it's hit or miss.