Tax Included means that you sell a service/product at the same price for all customers
at all times in all countries. The excluded tax amount will be all time the same,
100€ for instance. And the taxes will be calculated before the payments during the
checkout and added to the excluded tax price depending on your customer evidence
(Business or Consumer, Billing Country, IP address, Credit card country), your tax
threshold, and the nature of the item sold.