I've modified some of the files in my install of itflow. I am not sure that the way I did it is best, so I am not sure I should submit a PR. I basically just checked to see if the agent had the financial toggle enabled, and if not, hid all the billing stuff on the left menu.
I am sure there's a better way. I saw a lookupPermissions or something to that effect that could be used for it instead.
I still think that something similar to what I did be added to ITFlow.