One proposed sale should become one connected transaction.
A pro forma can show a customer what the deal should look like. Belvara keeps the customer, pricing, order, stock, payment and final invoice connected when that deal becomes real.
Move from proposal to order without re-entering the details.
Keep preliminary documents separate from final invoices.
Keep payments, fulfilment and customer history visible.
Carry the commercial trail through to the final sale.
One sale should happen once. Not once in the pro forma, once in a message, once in an order sheet and once again when you issue the final invoice.