Why is my online store's tax calculation incorrect?

[PartyTime]

Recently I have taken notice that the tax generated on our store is not correct. Take the following example of a small order containing 2 of the same product. Each product is 11.50, inclusive of the tax already and shipping is not taxed. 

Breaking this down, per individual line item, 18% of 11.50 is 2.07, this would mean our taxable amount should total to 4.14, but is stated to be 4.27. Similar cases have been found. Am I calculating something incorrectly here? Is there something I am missing?

[Themeborne]

Same issue here. Hoping some answers will come through soon!

[accounting1]

I have the same issue and I am chatting with them at the moment to see wehat is happening with their tax software.

[cnrtncy]

Same issue here. 
e.g.

Product Price(Tax included): 100

Tax: 10%
No Shipping tax added.

Result: 

Calculated tax is 9.12 (something like that)

I have no idea where 9.12 come from.

[Rostislav]

Should be 9.09

100/110*10=9,09 - tax inclusive 

[Rostislav]

Hi,  Party time

Why do you think that shipping is not taxable? Since the delivery is to the EU and the tax is calculated, your shipping is always taxable . So in your order you have 23/118*18= 3.51 VAT on goods and 5/118*18=0,76 on shipping. Total 3.51+0.76=4.27. VAt is applied to shipping even if the box is not checked (see the explanation next to the box): 

This is correct behavior. Shipping is not sold separately it is part of the order cost and is considered in the EU and UK as incidental cost/ service and internally is to be levied with the same VAT as the underlying goods. When it comes to international sales ,  UCC (EU union customs code ) considers shipping to be a part of the customs value  and it is to be levied with duties and VAT.