Facts:

Halliburton West Africa Limited, the appellant is a company incorporated in the Cayman Islands. In Nigeria it incorporated “Halliburton Energy Services Nigeria Limited” or “Halliburton Nigeria”. Both companies agreed that contracts won in Nigeria would be executed Halliburton Nigeria, then bill for work done under those contracts in United States Dollars. By this arrangement, the appellant derived income from the services rendered by the appellant and Halliburton Nigeria to those parties, although Halliburton Nigeria retained money in Naira for its working capital requirements. Halliburton Nigeria was paid by the appellant 100 per cent of its operating expenses in executing the contracts in Nigeria plus a management fee of the equivalent of 4 per cent of the appellant’s revenue derived in Nigeria from such contracts.

The appellant filed self Assessment Tax Returns for the years 1996, 1997, 1998 and 1999. The Tax liabilities arising from the Tax Returns were duly paid by the appellant. In 2002, the FBIR issued Notices of Additional Assessments to tax to the appellant in the total sum of US$6,972,248 for the same Tax periods of 1996, 1997, 1998 and 1999. The appellant challenged the validity of these assessments.