Ben -- I don't get how you were able to use UPDATED for Bruce's user case.
If I understand it right, when a user if on a Form, Bruce wants to save the form if a certain text field value WAS CHANGED. I'm assuming Bruce wants to save it dynamically while the user is still on the Form and has not clicked any buttons to save the Form.
To test UPDATE theory, I added two attributes to RegularUser, Test1 and Test2.
Then I added a dynamic rule:
If RegularUser.Test1 WAS CHANGED Then
RegularUser.Test2=RegularUser.Test1
UPDATE RegularUser
When testing, I tried to update RegularUser.Test1 and tab through it hoping it would update the Test2 value and commit the values to the database.
I got an internal error.