Hello
While integrating our billing system with the FreeAgent API; we have faced an issue involving multi-currency invoices. 
Specifically; when creating an invoice in a non-base currency (e.g., USD for a GBP account); we attempt to override the exchange rate using the documented exchange_rate field.
However; FreeAgent appears to ignore this override and instead uses its own historical rate, leading to inconsistencies in revenue reporting. 
This is problematic for us because our internal financial records rely on the exchange rate provided by our ERP; which can differ from FreeAgent’s default. While the UI allows some flexibility with manual input, the API seems rigid & doesn’t accept the custom rate even when passed correctly in the payload. I have checked FreeAgent Developer Dashboard guide related to this and found it quite informative. Also as we integrate financial data with CRM tools to align with what is marketing automation, consistent exchange rates become crucial for accurate revenue attribution across platforms.
Has anyone successfully used the API to enforce a custom exchange rate on invoice creation? / is there an official workaround such as posting adjustments via journal entries—to correct the accounting after the fact?
Thank you !! 