I can understand Extra request and can approved it in one condition – we will issue the invoice for cash payment, without any credit terms.
That means – we will use today's exchange rate, issue the invoice, and the payment will be done by tomorrow, the latest.
If they accept to pay those 2 orders in advance( before we actually supply it) ,
we can do as their request, otherwise, we will issue the invoice according to the product arrival & supply.