Is the rate date used to convert Txn Value to Standardized Value the order submission date?

Summary:

We are using OM.
And the transaction currency is set to Japanese Yen.
In this state, we registered US Dollar as the Order Currency and submitted the sales order.

At this time, the US dollar price will be displayed in the Transactional Value in the Fulfillment view.
And the JPY price will be displayed in the Standardized Value.
Is the rate date used to convert from US dollars to JPY the order date?
Or is it the system date when the sales order was submitted?

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