IHTM31603 - Assessing: repayments: authority to repay
Repayments can be prepared up to the Sect 6 stage (including any calculation of repayment interest due) by caseworkers at AO or above who have the appropriate COMPASS role. If you have any doubt about the repayment calculations, take advice. It is no reflection on your ability if you seek advice.
Remember that you may need to get additional information from the taxpayer or agent to process a repayment (IHTM31663) over £150,000.