This Article outlines the tax accounting treatment for long-term contracts under the accrual method. It stipulates that a taxpayer must calculate income and expenses based on the percentage of work completed within the taxable year. The completion percentage is determined by comparing the contract costs incurred during the year with the total estimated costs of the entire contract. The text defines a 'long-term contract' as one for manufacturing, installation, construction, or related services that is not completed in the same year it commenced. However, it explicitly excludes contracts expected to be completed within six months of their start date.