Question regarding price-match - Travel agency

1). I own a Travel agency and sell cruises. Many times I give onboard credits to my clients as a part of a  "price-match".  How do I categorize this expense (price match)?

2) I offered a client to pay for a trip expense that was entered in the system incorrect (new system glitch, not the customer's error)..  I will refund the client for the expense.  How do I categorize this system error?  Is there like an errors en omissions expense?

Thank you in advance.