Incorrectly calculated the tax value of the OPC
My TAX settings:
American settings: YES
Product unit price at checkout: CANADIAN
Subtotal at the checkout: CANADIAN
Coupon price at the checkout: whitout Tax
Plugin Discounts: NO
...
Show just one tax: NO
Show dynamic lines: YES
If "show just one tax" - is checked, the VAT calculation good
If "show just one tax" - is unchecked, the VAT calculation false.