My entity's base currency is in SGD. My problem here is that there's a separate agreed rate with the customer when knocking off the SGD invoices against the USD payment.
1. Payment of USD50,000 SGD65,500 posted in the system based on the currency exchange rate set in the system.
2. When USD Sales invoices are posted, it's using the exchange rate at posting date set in the system.
3. When SGD Sales Invoices are posted, there is no exchange rate conversion since our currency is SGD.
Example:
1. Payment posted in Oct USD50,000 SGD65,500 (system exchange rate of 1.31 for Oct)
2. USD Sales Invoices posted in Nov USD30,000 SGD39,600 (system exchange rate of 1.32 for Nov)
3. SGD Sales invoices posted in Dec SGD25,000 (no exchange rate as base currency is SGD)
Agreement with customer - USD50,000 converted at 1.30 (SGD65,000) to settle the above invoices (Point 2 & 3).
Seems to me that the only way is to post a journal manually to capture the exchange differences.