Answer
When you edit a pay, the Leave Balances screen shows annual holidays in weeks and sick leave and alternative holidays in days. These balances are read-only on the pay screen so the pay cannot overwrite the statutory leave ledger.
Use the pay screen to review balances and open How is this balance calculated?. Use Employees >> Leave >> Leave Entitlement Adjustments when a balance needs to be changed.
This keeps leave taken, anniversary grants, cash-ups, and manual corrections in one auditable ledger.