Payment Exceptions in Toast allow a payment to be made without an actual sale and then, at a later date, a sale to be made without an actual payment.
Typically, this is best handled by using a Clearing Account of some sort in the Other Current Assets section of your balance sheet chart of accounts. You would not, typically, want to map Payment Exceptions directly to a bank account, as the payments/deposits will come through via the actual payment mechanism (e.g. credit card, cash, etc).
For example, if you accepted a Visa payment today on an order for fulfillment tomorrow, the accounting would be:
Credit: Payment Exceptions Clearing
Debit: Payment Exceptions Clearing
If you add a new account to handle these in your accounting system, you can refresh this in your Shogo accounting details and then map to the new account at:
>Settings>Accounting>Refresh Reference Data
followed by updating your mapping at: