VAT Exchange rate
According to Polish Law, in some business cases, there is a necessity to post a foreign currency invoice with two various exchange rates for CIT and VAT purposes.
There is a possibility to open BKPF-TXKRS field for entry of tax (VAT) exchange rate and setting the parameter responsible for currency translation for tax items in Company Code basic settings (Fig1 & Fig2)

Fig1. Company Code configuration

Fig3. “Plants abroad” activation
Without this setting, tax exchange rate is taken into consideration only for translation of tax amount, but tax base amount is translated with document header exchange rate (field BKPF-KURSF).
In many cases, especially when one SAP instance is used in many company codes from various countries, there is no possibility to activate “plants abroad”, as this is not company dependent setting (it is client dependent). Activation causes additional configuration changes of company codes and tax schemes for countries which would not use this functionality. That’s why so often, central IT team responsible for SAP in the Organization doesn’t allow to activate “plants abroad” (if it’s not active from the beginning of SAP usage) during roll-outs to Polish company codes.
Lack of “plants abroad” activation causes that there is no value in BSET fields LWBAS and LWSTE for document. These fields should contain PLN amounts translated with tax exchange rate (TXKRS) and these amounts are shown in VAT register an SAF-T files (JPK). That’s why lack of values or incorrect exchange rate used to calculate them causes necessity of manual or ABAP interference into SAF-T files generated from SAP.
Below you can find kind of workaround solution that allows to maintain tax base amount in local currency while posting document. Such solution can be used when we have no possibility to activate “plants abroad” and to prepare configuration according to OSS note 730466.
SPRO configuration path (Fig4) allows to maintain following steps:

Fig4. SPRO configuration for VAT control
Step 1 is needed only on development environment. Steps 2 and 3 should be transported onto test and production environments.
Step 1. Change message control for message no FF 116 on development system (t-code OBA5) – it can be maintained only for specific user that prepares configuration – message shpuld be set as warning:

Step 2. New entry for TAXPL scheme – for Poland this is possible only after change message control shown in step 1:

Step 3. New entry for TAXPL scheme – it will cause that manually entered tax base in local currency will be not updated by system calculation.:

Above settings allows you to manually enter tax base amount in local currency while FB60 or MIRO posting.
It will be possible to enter tax base amount translated with tax exchange rate, and therefore proper show of such documents in VAT register and SAF-T (JPK) files without manual interference into these files and without ABAP changes in RFUMSV00 report (VAT register).