Final answer:
The direct write-off method records expenses when a customer's account is deemed uncollectible, not at the time of the related credit sale, which causes a mismatch of revenue and expenses as per the matching principle.
Step-by-step explanation:
The direct write-off method mismatches revenues with expenses because a customer's account is expensed in the period when the account is deemed uncollectible not when the related credit sale occurs. This is contrary to the matching principle, which advises that expenses should be recorded in the same accounting period as the revenues that are associated with those expenses. In the case of a credit card, the money is immediately transferred from the credit card company's account to the seller, but the debt is realized by the user at the end of the month, which is when they owe the credit card company.