It seems the issue is to get the menu to update when the value returned by the calculation changes. I found that if I used a global variable for a menu option name, I couldn't change the value of the variable and see the change appear in the menu unless I cycled from browse to layout mode and back to browse again.
After some experimentation, I found I could use the script step: Install Menu Set to re-install the specified menu to force the menu to update and show the change in value.
Thus, you can probably get this to work with a script that uses this step to referesh the items listed in your menu after a value is changed.
Works well with loading a new menu.