Jackrabbit defines an Account Credit as an amount that is posted to a family's account to reduce their balance owing without any exchange of money. Some examples of Account Credits are Groupons, gift certificates, scholarships, barter credits, fundraising credits, or credits for future fees.
This is different than a refund where money is actually given back to the customer. If you need to refund a payment, see Post / Enter a Refund.
Account Credits are posted using the Payment button in the Family record with a transaction type (Pmt Type) of anything other than Payment (Credit). This is to keep these amounts out of your revenue reports. Payment Method drop-down values can be added for the various types of credits you issue to help you to report on these non-revenue amounts.