Why is my sale proceeds placed in available cash and not returned to my bank account?
This is a feature for ledger based account(PCMA, Cash Prepaid, Custodian, Margin & Share Financing) where these accounts provide ledger facility for you to manage your cash in your trading account.
This available cash can be used to settle your future trades automatically. No further settlement instruction is required so long as you ensure sufficient funds available for the settlement.
You can also withdraw the available cash anytime; there is no lock-in period or additional fees for the withdrawal.