I am unclear as to exactly where your issue is occurring.
Is it when a EUR order is originally used to place the order, client changes to EUR when prior to ordering?
Is it when an order is added to the cart in USD and customer changes it to EUR prior to paying?
Is it when an order is already placed and the customer is reordering?
As AbanteCart indicated the timing of the currency change can affect the total pricing. Also what cart version are you using, some of the previous issues with this have been corrected in 1.2.16
1st of all, We sale fabrics and we modified the codes on different files and folders and on database to activate
(cm) calculation and sales. We specified the sales to be started with the minimum of
(100 meters) Now... Client when he wanna start put his items in the basket, go to currencies and choose the required currency then starting the shopping until placing his order and getting an order number. Now, The sales department should check the quantities with warehouse department and edit the order and write the exactly available quantities with the
(cm) if that required and save order. During this the issues which I talked about become seeable. When admin changing the order status to inform the client about the new order details, clients become confused because as I said they see differences in the information from out side of the order and not satisfying the same from inside the order.
Thanks...