Data-Visualisation and the Users Expectations

I am currently working on an app to do with pensions. I have a graphical representation showing how much the user will have at their chosen retirement age; these are based on defined contributions and benefits ect.

What are the rules if any, around making graphs and or other graphical visualisations interactive; in so far that the user can physically alter the data directly? Should the user still be given levers and switches to make the same amends?

Cheers

I have attached an image to illustrate further.