If your customer's home loan account starts with BSB 182, their repayment amount is based on the home loan account limit and a limit reduction is likely to reduce the minimum monthly repayment amount.
If your customer's home loan account starts with BSB 183, their repayment amount is based on the home loan account balance. A limit reduction is unlikely to reduce the minimum monthly repayment amount.
Example (for BSB starting with 182): The loan limit on your customers home loan is $500,000, the balance is $400,000 with $100,000 in redraw and minimum monthly repayments of $2,000. Your customer may be eligible to reduce the limit to $400,000 (using the funds available in redraw) to permanently reduce their limit. As a result, the minimum monthly repayment is reduced to $1,700 for the remaining loan term. (All figures are approximate and provided by way of example only).