Your settings are:
1. In the product card, the price with VAT
2. In the product cards there is "VAT amount of the product" -20%
3. Legal entity FOP indicated VAT - 0%
4. Legal entity TOV indicated VAT -20%
5. There is a check mark on the item "Calculation of the amount with VAT from the rounded value of the price without VAT"
You issue invoices by choosing a legal entity.
If everything is correct and the problem remains, then I can offer to give me access to Boxing by e-mail
olmoniccrm@gmail.com, I will look at examples of calculations in your Boxing.