For this case, if the invoice currency is different from the invoice company currency, the tax calculation is considered the value in a different currency, and the subtotal is the sum of the amount untaxed + the taxes (wrongly in company currency) result in an incorrect value. This is verified when printing the invoice report

closes odoo/odoo#62386

X-original-commit: 91f152f4
Signed-off-by: Josse Colpaert <jco@openerp.com>