How to change VAT to 20% in 1s-bitrix??

Question

1C-Bitrix

At the beginning of the year, the VAT rate was changed from 18% to 20%. It was written on the site that if you have a lot of goods, then you do not need to create a new VAT, but redo 18 to 20 in the name and rate. That's exactly what I did. But the problem is that I choose goods worth 300 rubles, and VAT of them is 50 rubles, this is not 18%, and not 20%, but 16.7%. What is the problem ? No promotions or discounts

Answer 1

120/300*50 = 20
120 is 100 + 20