Check the sources:
1. Client rate — is the monthly rate correct in all active client profiles?
2. Fixed costs — are there active costs that no longer apply?
3. One-off entries — are they entered twice?
4. Employee deduction — under Financials → Employee costs you can configure deductions per linked employee. One wrong entry lowers both commission and view on client revenue.
5. Manual override — sometimes replaces the automatically calculated amount
Fix the cause and the calculation updates immediately.