Field help (TPYRATINV) 

If this check box is selected for an invoice in a currency different from the company currency, the exchange rate applied between the open item currency for the closing of the BP account (closed during the first posting step) is the same as the rate on the invoice. There is no exchange rate variance journal reported in the company currency. 

If this check box is not selected, the exchange rate applied between the open item currency and the company currency for the closing of the BP account is the exchange rate on the posting date. For an exchange rate variance, an exchange rate variance journal in company currency is generated. 

Note: This check box is also relevant for the reporting currency for which an exchange rate variance journal in the reporting currency can be generated, or not, depending on whether it is selected or not.

This exchange rate is applicable to the Bank or BP payment type attributes and uniquely for the cases where one (or more) invoice is posted. For other payment attributes or non-posted Bank or BP payment attributes, the retained exchange rate is fixed with respect to the exchange rate type previously specified.

At the same time as the application of this original invoice exchange rate, several rates can co-exist. In this case, the accounting journal displays a blank exchange rate and suggests an exchange rate as an inlay on the screen.

  If the Main ledger currency rate check box on the Entry tab is selected, this field is disabled.