Perhaps think about FO not as accounting system but activity logging system with excellent document control.
You could create workspaces for each case# with a child workspaces for:
* Client Documentation
* Court documentation (pleadings, filings, etc)
* Legal Briefs
* Research Documents
* Case Emails (exchanged with the client or others, internal or external)
* Outside Service Charge documents, etc.
* Billing
Under Billing, create additional child workspaces:
**Open (unpaid) Invoices
** Closed (paid) Invoices
Have bookkeeper upload scanned copies of invoices to the Invoice workspace. When payment comes in, bookkeeper scan a copy of the payment advice, check, whatever, and upload to closed invoices. Then bookkeeper matches the payment with the related invoice and drags/moves the paid invoice to closed invoice workspace.
Anyone with adequate permission to access various workspace may subscribe to the workspaces and get automatic notification of the activities.
There's no real benefit with respect to the bookkeeping.
But, for timekeeping and and associating emails and other documentation with the work performed, and keeping all related case documentation in one place? Now that could make ongoing and future review of case files, complete with billings, much more efficient and easier for your service professionals.
Don't know it that helps, but off the cuff, may give you some ideas.
Cheers,
Charles