VAT calculation not correct

[Arianna_Fra]

Hi Everybody,

I've set VAT at 22%, but calculation seems to be wrong, it's like Mageto is calculating 18% VAT instead of 22%( http://awesomescreenshot.com/0295xl6z19 )

The System > Configuration > Sales> Tax  section is configured as this:

http://awesomescreenshot.com/0fa5wyeg5e

http://awesomescreenshot.com/0555wyei3f

http://awesomescreenshot.com/0215wyej17

Tax rate is set as this: http://awesomescreenshot.com/0115xl7oe4

Tax rule is set as this: http://awesomescreenshot.com/0a75xl84ce

There are no discount on products

Could it be a Magento bug?I use CE 1.9.2.4 version

Thanks in advance to everybody!