Apple will formally appeal the European Commission's demand for €13 billion in back taxes this week. It argues the EU inaccurately came up with the figure and that Apple cannot pay the back taxes without violating prior Irish tax laws. Bruce Sewell, Apple's general counsel, says the EU ignored a lower proposed settlement generated by Ireland's chosen tax experts.

The company believes its two Irish entities are real and don't exist solely for tax purposes. That's a point where the EU holds a completely opposite opinion, arguing the Irish companies aren't legitimate.

Under the proposed tax models from the named experts, Apple says it would have been ordered to pay a "much lower" amount. EU officials allegedly decided to ignore that proposal for the sake of maximizing the financial impact of the ruling.