Hi,
I am assuming you would have stored original line items and settlement line items in 2 different cubes, then you can the following 2 options,
1. Create a report on Settlement line item and then create another report on original line items, then link using RRI concept, After executing the first report, if you wish to see the details, then you can go to second report from the context menu of query output.
2. Create a multiprovider on 2 the cubes, Create 2 restricted keyfigures one $ amount restricted with Settlement cube and other keyfigure $ amount restricted with Original cube, based on the char selections you wish to choose, you can get both of them.
I would say, the first option is easy to do.