The "Display taxes of this type inclusive in product prices" is used for more than just display

Problem/Motivation

The "Display taxes of this type inclusive in product prices" is used for more than just display.

I had an issue where the shipping costs were handled as they are including VAT so did not Respect the store's tax setting 🐛 Respect the store's tax setting Needs work However I noticed that the "Display taxes of this type inclusive in product prices" inherited from the order as described by @bojan in #2874158 → is used not only for display but for working out if the price is including or excluding VAT.

Example 1:

• Shipping £10.00
• "Display taxes of this type inclusive in product prices" = Yes
• VAT calulated to be £1.67

Example 2:

• Shipping £10.00
• "Display taxes of this type inclusive in product prices" = No
• VAT calulated to be £2

In my case, the issue was solved by unticking the box and I had no time to investigate so seeing as a feature request, however, it is probably a bug and related to #3189727