Iron Python for Calculated Value Merged

As a developer i have a lot of calculated values existing in text areas. The values can be updated based on markings throughout the page just like any other visualization. I have some iron python scripts that are set up inside the dxp that will update visualizations based on user action. This involves something outside the scope of just a normal marking function. For instance, i can updated the custom expression in the visualization and the formatting for each value. 

In the Iron Python scripting i can reference pages, visualization, and document properties as parameters outside the script or variables inside the script. I would like to also reference calculated values that have been created. 

Use Case: I have a calculated value in a text area showing the grand total for revenue. The user has the option to change their metric between revenue, volume, weight, and yield. I would like my calculated value to updated based on user selection (i can do this currently) and also be formatted correctly (i can not do this currently). If there were a python script that would allow me to reference the calculated value....i could update the formatting on the fly.