Apple has attempted to school the European Commission on how it interprets Irish law, by lodging no less than 14 pleas in its challenge against competition officials in Brussels who have ordered the iPhone maker to pay Ireland €13 billion (£11.1 billion) in back taxes.

The company claimed that the commission was wrong in its conclusion that Apple's tax arrangements with Dublin had amounted to a sweetheart deal for more than a decade, thereby breaking state aid rules.

Apple, in a bold dismissal of the case, is seeking a full or partial annulment and wants the commission—which is the executive arm of the European Union—to pay its legal costs.

It claimed in its legal argument that the EC's competition office, headed up by commissioner Margrethe Vestager, had made "fundamental errors" in its assessment of Apple's tax deal with the Irish government. The Cupertino-based multinational's two firms in Ireland, Apple Sales International (ASI) and Apple Operations Europe (AOE), enjoy dubiously low—but legal—tax rates. In one of its pleas, Apple characterised that arrangement as perfectly acceptable, alleging:

The commission presumed that all of the applicants’ critical profit-making activities were attributable to the Irish branches without properly assessing the evidence, including extensive expert evidence showing that the profits were not attributable to activities in Ireland.

In a related plea, Apple claimed that its "Irish branches carried out only routine functions and were not involved in the development and commercialisation of Apple IP which drove profits."

The tech giant also claimed that the commission had "failed to conduct a diligent and impartial investigation," and accused it of breaching the Charter of Fundamental Rights of the EU. It also questioned the "competence" of Brussels' antitrust wing. Apple said:

The commission has violated legal certainty by ordering recovery under an unforeseeable interpretation of state aid law; failed to examine all relevant evidence contrary to its obligation of due diligence; failed to reason the decision adequately; and exceeded its competence under Article 107 TFEU by attempting to redesign Ireland’s corporate tax system.

Many of Apple's allegations mirror that of the Irish government, which recently insisted that its tax arrangements with the Tim Cook-run company didn't amount to favourable treatment.

Dublin, among other things, has accused Vestager's office of failing to understand "the activities and responsibilities of the Irish branches of ASI and AOE," by claiming that they only "carried out routine functions."

In a short statement to Ars, the EC recycled its earlier comment on the case: "The commission will defend its decision in court," it said. The hearing is expected later this year.