Getting the latest currency values for despatch/invoice when using forex

BlueBox2.0 is a multi-currency platform, and uses a strict parent-to-child value transfer when migrating data from document to document. This is handy in most instances, but can cause come discrepancy when the document is captured in a forex currency.

If the time difference between the date a Sales Order is captured varies significantly from the date the subsequent Despatch or Invoice are generated you can find that the forex variation is great. The 'spot rate' is stored in the original Sales Order and is then copied onto the downline documents (Despatch/Invoice) causing a widening forex difference if the IMF sport rate changed between the dates of the documents.

To get around this we have introduced a new bbsetting called bbsetting_force_latest_forex_currency_when_copying_from_parent which, when set on a module like bb_sales_despatch_notes and/or bb_sales_debtors_invoices will force the system to check the date and value of the most recent currency entries and warn the user if the currency table is out of date. 

It then also forces the latest currency value into the 'forward rate' box, thereby retaining the original 'spot rate' captured in the Sales Order and overriding this with the latest rate as the 'forward rate'.

Though this is not strictly a 'forward rate' it does the job perfectly. Obviously if a forward rate were set in the Sales Order originally then this override would not kick in as it would not be required.