Exchange Rate Issues in AX

I have always wanted to know how exchange rates behave in AX (as to when the auto posting to realized accounts happen and when it doesn't). I did some testing and this is what i thought i should record, before i forget.

11. Exchange Rate difference postings to realized exchange rate profit and loss accounts happen automatically when the sales invoice and the payment is in different currency than the company currency AND the payment is posted in the system on the date other than the invoice date.

Company Currency - GBP

Transaction Currency - USD

Exchange rate GBP / USD is different on the date of invoice and on the date of payment.

Based on the scenario mentioned above, if there are any exchange rate gain or loss, then it is AUTOMATICALLY posted.

22. If the sales invoice is in the company currency (GBP) and the payment is posted in transaction currency (USD), then the exchange rate posting will NOT be done automatically to the exchange rate gain or loss accounts. System will take the exchange rate defined in the system, calculate the value and post it in the system. However there are many different scenarios to it:

•      If there arises the need to change the exchange rate, then it can be done by changing the Cross rate. If the cross rate is changed, then the auto postings take place in the exchange rate profit and loss accounts.
•             If there arises the need to change the exchange rate, it can also be changed from the general tab by actually changing the exchange rate. However this will not change the amount in the journal and the journal will post. This will automatically not post to exchange rate profit and loss accounts. The only thing system will do in this case is, it will determine the value based on the exchange rate changed and then will either keep the invoice open or the payment open on the customer account.    

33. There is also one more scenario which is of credit note. If the invoice is raised in different currency than the company currency on certain date. After few days if the credit note is to be raised for the same, then what exchange rate the credit note should have, is the question. To manage this there is a setting in Sales Ledger parameters (Updates - Use exchange rate from source document) . If we do not turn the parameter on and go ahead the try to raise the credit note, then system complains and gives error, as the value does not match because of exchange rate fluctuations. The setting that I am talking about makes sure that the credit note also has the same exchange rate that of invoice. On the projects side though this thing can be managed, if the contract is a fixed rate contract.   

Just wanted to note this down so that I wont forget in the long run.

Kind Regards

Sarang