Checking funds at PO level

 Hi, I have the following issue:

I create an expense PO connected to a project with budget 1000$. This budget control for this project is defined in advisory mode. The value of PO is 100 000 $ so it exceed budget significantly. When I check funds for this PO, I got information - 'Your budgetary Control action completed sucesfully'. Then I approve and reserve funds for this PO and match this PO to the invoice. When I check funds at the invoice level, the result is the same -  budgetary Control action completed sucesfully. But when I create a invocie, not matched with any PO, with the same data which was on