I am deploying Odoo V9 in Colombia and am entering my inventory (purchased in USD) that I have had since the beginning of 2015. I have already enabled multi-currency and imported the USD/COP exchange rates for every day in 2015.  

Let's say I enter a retroactive Purchase Order for PRODUCT1 for June 1, 2015.  I would expect that Odoo calculates the Inventory Valuation using the exchange rate on June 1, 2015, but rather it seems to use the most recent exchange rate available (say Dec 31, 2015 in this case).  

Is this right?  Q: Is my inventory valuation for everything supposed to be based on today's exchange rate? or is it supposed to be based on the exchange rate of the purchase date?

This doesn't seem right and according to this article it should be based on the purchase or BS date:
http://www.accountingweb.co.uk/anyanswers/valuing-stock-year-end

If anyone can clarify how I can remediate this situation and retroactively enter foreign purchases with the correct exchange rate it would be very helpful.

Thanks,

Adam