Income shall be computed as provided by this Decree and in accordance with the method of the commercial accounting regularly employed by the Taxpayer in keeping its records. If the method so employed does not fairly reflect the Taxpayer's income, the computation shall be made in accordance with such method as does fairly reflect its income. The accrual method of commercial accounting (that is, the method under which item of incomings and items of deduction are taken into account in the Taxable Period in which they accrue, that is to say, in which the right thereto or the liability therefore arises and the amount thereof becomes reasonably determinable) shall be considered as fairly reflecting the income. The Taxpayer shall be entitled to use the method regularly followed in its records for converting one currency to another, if such method is generally recognized in commercial accounting.

The terms "accrue to or are received by", "accrue against or are paid by", "accrue to or are paid", "incurred or paid" and "derived", when used in this Decree, shall be applied and constructed in accordance with the method of commercial accounting upon the basis of which income is computed. Accordingly, if income is computed on the accrual method of commercial accounting, all items of incomings shall be taken into account for the taxable period in which they accrue to the taxpayer, and all items of deduction shall be deducted for the taxable period in which they accrue to the taxpayer. While if income is computed on the cash receipts and disbursements method of commercial accounting, all items of incoming shall be taken into account for the taxable period in which they are received and all items of deduction shall be deducted for the taxable period in which they are paid by the taxpayer.