What is the point of entering a payment from a customer who does not have an invoice? I see that I can add a payment without having to select an invoice, which is a nice feature, but I cannot assign an amount to that payment. My customers must confirm quotes by paying a deposit. No invoice will be made for that advance payment. So it would be useful if I could link a payment to a quote, or simply link a payment to the customer, but with an amount and not just 0.