The Interest Calculator program is only set to be an Accounts Program.
This can be run via Client/Matter or all matters and then updated to the matter which is why it is accounts only function.
If the fee earners need to see a value in the Desktop then there would be a way to create calculated fields to work this out from figures put in.
If you require help with the fields then this would be Consultancy, please raise a new case online and reference the title of this article.