In 1000 already 800 has PO commitment, so available budget is 200 only. while invoice, system
checks the invoice value 800 with available budget i.e. 200, so difference of 600 and it'll shows the error.
i would suggest you to exclude PO-02 from tolerance group, then system checks budget availability on remaining list in the tolerance group.
suppose if you exclude IR-04 from tolerance group then actual cost will get posted more than your budgeted value and no use of budget.
regards,
