Contract - PO conditions to be not considered in the contract consumption

Hi experts,

I am having problems with the balance consumption of a contract in importation process.

The problem

The value contract is created to the foreign vendor, for example, 1 Milion USD.

In each PO created against the contract, there are some conditions that are paid to local vendors and not to the foreign vendor, such as the forwarding agent, insurer, taxes, etc. It was created a condition in the PO for each of these costs of the importation.

The problem is that these conditions also consume the value/balance of the contract. When the value to be paid to the foreign vendor is about USD 700~900 thousand the consumption of the contract is already completed due to the conditions.

The question

Are there any way the system does not consider certain conditions in the contract balance when the PO is created?

Best regards,

Rafael