When creating Purchase Order, I receive quotes with a different currency, however the final price is given that includes the taxes in my currency.

As the currency is calculated on the day, it might differ slightly on another day - thus I can't use a formula/converter.

To ensure my bill matches PO, I need to be able to set item prices individually (final price) that have taxes already included. 

At the moment I can only guestimate (guess an estimate ) of the individual amount and hope it balances.

Example:
Purchas Order
Product           quantiy  Unit Price     Taxes  excl           Taxes  incl​

Wine               x20                  ????????           22%                      400.00   

If I order wine per crate, as per example I get the total amount for the crate and not the individual price per bottle- so the invoice shows taxes on the crate and not on individual items. And due to working in multiple currencies all of these fluctuations in price causes discrepancies. 

I don't want to receive the item as 1 unit crate, but rather as 20 items for stock purposes.

Any advice would be appreciated

Kind Regards,
Helena