Settlement

A merchant invoice is what the platform charged a merchant for a period, and what has been paid against it.

Reading one invoice fills in items and billing; a listing leaves them out. manualPayment is how a person pays it without a stored source.

status is a ladder, not a flag: Outstanding → NearDue → Due → Overdue, and payment is required from Due. payments is every attempt at paying it, and it is where to look before marking an invoice paid by hand, an MinvPaymentInProgress at the end of that list means a direct debit is in flight and you would be double-crediting.