I fear i have found a severe bug or misconfiguration in Foxycart regarding tax calculation. Basically we have 2 nearly identical shops
(one currently configured for Single-sign in and the other for guest-only checkout). If i put the EXACT same product in both shops i see different values for taxes
and after digging into the cause of this, i found that the taxes are not applied to the shipping in the same way
I prepared here some images for you, that should make it simple to understand the problem. You see 2 screenshots for each Shop.http://imgur.com/a/WiJlA
See that the taxes are applied for the shipping on Shop A but not for Shop B (although as you can see the settings are absolutely equal!). Don't worry also the category for the product is defintely correct and the same.
I see that the checkbox to apply taxes to shipping is not always visible in the admin panel. It seems it is only visible for global taxes or so. Could it be that you changed this and internally Shop A still has this flag set to true in your database?? As a short quick fix could you just enable the taxes for shipping in our shop B
? We wanted to release today :P The shop domain for the non working Shop B is "fileeepremium". Shop name is "fileee". For Shop A(where it works correctly) the domain is just "fileee"