Once an allowance for doubtful debts has been created, only the movement in the allowance will need to be charged to the income statement in future accounting period. So if estimated allowance for doubtful debt is same as last accounting period, no accounting entry will be required in the current period as the total receivables will be reduced by the amount of allowance which has already been created. - See more at: http://accounting-simplified.com/accounting-for-doubtful-debts.html#sthash.11yHRlXa.dpuf