In 2020, Vaughn Company had net credit sales of $1124900. On January 1, 2020, Allowance for Doubtful Accounts had a credit balance of $28000. During 2020, $42700 of uncollectible accounts receivable were written off. Past experience indicates that the allowance should be 10% of the balance in receivables (percentage-of-receivables basis). If the accounts receivable balance at December 31 was $375300, what is the required adjustment to the Allowance for Doubtful Accounts at December 31, 2020?