Where do the Write off of $ 2000 for 2021 came from?

At December 31, 2020, Pinebrook Inc. had $155,000 of accounts receivable and $8,000 in the allowance for doubtful accounts. In 2021, the company had $720,000 in credit sales and collected $738,000 on accounts. Pinebrook also wrote off $4,500 for specific accounts determined to be uncollectible. The company uses the aging of accounts method to estimate bad debts, and management has estimated that the allowance for doubtful accounts for December 31, 2021, should be $5,500. Required Allowance for Doubtful Accounts Beg bal 5,500 Write-offs 2,000 BDE 1,000 End bal 4,500