Requisition / Std PO follows GBPA currency and not OU currency linked to the GBPA

Hi

The same question was once posed on the community but I see the article is removed.

We just roll out to a foreign country (Lesotho).

1. Blanket Agreement - supplier Waltons Pty Ltd GBPA currency is ZAR

2. Enabled the GBPA for the foreign country site whose currency is LSL

3. The user in Lesotho raised a requisition against the GBPA (Waltons Pty Ltd)

4. The requisition / purchase order follows the GBPA currency and not the OU specific currency

Is this standard Oracle functionality?

If yes, maybe a brief explanation of the logic....

I can possible understand why, if you buy on the internet from a different country,  the PO is in the overseas country's currency not in the currency I am residing.