Split Payments are available for orders, but not for invoices. Is that something that is even in the planning phases for invoices?
We can’t use orders for open balances, because the Orders API requires a payment transaction to be attached to the order, otherwise it won’t show up in the POS system. Therefore we have to use the Invoices API to push the open order from our SaaS product to the POS when they’ve chosen to “pay at check-in”.
Square is a great product, but no matter what we try to do, there’s always a catch that we have to try to work around.