A method for revision control within hearing-aid fitting software may include storing session fitting data for a plurality of fitting sessions of a hearing assistance device; displaying a graphical user interface, the graphical user interface including a list of the plurality of fitting sessions of the hearing assistance device, the graphical user interface allowing for selection of two or more fitting sessions for display; receiving a selection of a fitting session from the list; and in response to receiving the selection, updating the graphical user interface to include a response curve related to the selected fitting session.