As per ASC 450 (Accounting for contingencies), most likely amounts should be accrued for loss contingencies such as provision for uncollectible receivables. In case multiple amounts are equally likely, the minimum amount should be accrued and the range should be disclosed. Since the auditor has evidence that supports an allowance for doubtful debts between $1,500,000 to $1,800,000, the minimum amount of $1,500,000 should be recognized in the financial statements. The proposed adjustment entry will be $700,000 [$1,500,000 less $800,000 amounts already recorded].