Receivables ledger

Question:

P & Co maintain a receivables control account in the nominal ledger. At 30 November 20X0, the total of the list of individual balances extracted from the receivables ledger was £15,800, which did not agree with the balance on the receivables control account. An examination of the books revealed the following information, which can be used to reconcile the receivables ledger and the receivables control account.
1 The personal account of Mahmood was undercast by £90.
2 Yasmin’s balance of (debit) £780 had been omitted from the list of balances.
3 The January total of £8,900 in the sales daybook had been posted as £9,800.
4 A credit note to Charles for £1,000, plus VAT of £200, had been posted to the receivables control account as £1,200 and to Charles’ personal account as £1,000.
5 The total on the credit side of Edward’s personal account had been overcast by £150.

What is the revised total of the balances in the receivables ledger after the errors have been corrected?

Answer for reconciling ledger with control account is: 90+780+150-200= 820 which you then add to 1500.

I’m confused over why we completely ignore note 3 and why we treat Yasmin’s debit balance the same as Edward’s overcast balance and Mahmood’s undercast balance. Any explanations?