Generally, housing loan (not referring to mbb) repayment works this way ....

1. If borrower pays the stipulated monthly amount, then there is no problem with interest or principal figures.

2. If borrower pays more than the stipulated monthly amount (eg 2 months), the extra payment will be treated as advance instalment for the following month and interest will be charged as normal.

3. If borrower wants to part settle the principal, normally have to give notice to the bank and they will then deduct from the principal. The next interest chargeable will be based on the reduced amount.

Outstanding Loan is the amount borrowed.
Balance outstanding is the amount repayable (principal + interest)

Same with Credit Card terms ...

Credit Limit is the card limit shown no matter how much one has charged the card.
Balance outstanding is the amount of charged transactions minus repayments, if any.
If Balance Outstanding = Credit Limit, then the card cannot be charged further.

For SI, the money should come from Savings/Current account. If don't have one, then have to open an account.

Different banks may only have slightly different procedures and terminology but it won't be far off.

Whatever procedures, bank won't rugi but borrower must monitor their statement to ensure it is correct.

Try RHB & PB