Thanks for the answer Charlene! It makes sense that I cannot filter a Statement of Cash Flows by class and get accurate cash flow data if the payments cannot be classed. If this is simply the way QB works, there's not much I can do about that. With that said, it seems like an odd choice from a program design perspective. It would make more sense to me to have a program that matches the classes of payments to the classes of the invoices that those payments are applied to. Maybe in a future release?