When a gap claim benefit amount is processed, the customer pays the gap amount, and their account balance is adjusted using a Credit Adjustment to reflect the benefit amount.

This in inadequate from an accounting perspective, as credit adjustments affect total sales, and the benefit amount is not reflected in the practice income.
They need to be treated as a payment against the customer's account, as the payment will be made by the insurer.

To accurately reflect practice income, the Credit Adjustment needs to be replaced with a Payment containing a Payment Other record, with a Payment Type of Gap Payment.

As payments require a till, each practice location will need a 'Gap Payment Till'. If no till is configured, one will be prompted for.